While I agree that AMEX should have just locked the account for fraud, one possible explanation that would create this scenario is a relationship breakup.
Man breaks up with his partner, and moves out of their shared home. He changes his phone number to be his new home.
Amex calls the old number, gets the old partner who is particularly vindictive and decides to answer the questions as well as he can.
When I worked in banking we had all sorts of issues about how we handled change of address with respect to relationship breakdown.
If a husband and wife share and account and share an address do you send them separate statements, or combine them? If the husband tells you he has changed address, do you assume the wife has changed too or assume that she's still at the old address? If he's on the phone, you can ask him but do you assume he's telling the truth?
If one member of a relationship chooses to change their mailing address, for security reasons, you might want to send a notice to their old address in case the change was fraudulent - but if they've changed their address because they're fleeing an abusive relationship then you can't send anything to the old address that indicates what the new address is. And just because someone at the old address raises an objection to the change that doesn't mean it was wrong, just that you need to do more investigation.
Those sorts of incidents were rare, but our procedures needed to plan for them.
And in this case, the correct action would be to lock the account and escalate to a superior.
The problem it creates is that you lose customers.
People want the ability to have joint accounts. A joint account generally has a credit limit set by the income of the higher-paid (or wealthier) of the two but allows both people to have a card and make payments. Imagine a simple scenario: one spouse works, the other does not; the one who doesn't work often does the shopping.
Others have mentioned the importance of joint savings accounts for married couples, and for businesses.
They're also very important for mortgages. If the mortgaged asset is jointly owned (and that's typically the case in a marriage) then you, in practice, need all owners to be a party to the loan. The house is security on the loan - if I only own half the house then I can only borrow against my half. And my wife can borrow against her half. But if I default on my loan, then how does my bank foreclose on me and sell their asset when there is another owner who may not wish to sell.
There are other solutions, but the easiest, and the one that banks will typically insist on is a joint asset requires a joint loan
People rarely think of this in advance, but joint debts of any kind usually become a problem in divorce. One former spouse will stop paying and ruin the other spouse's credit, to say nothing of causing foreclosures. It doesn't matter what the family court orders (this spouse will pay that debt, etc), because that won't change the underlying obligation as far as the creditor is concerned.
Joint credit cards, which aren't attached to any asset, don't have much benefit compared to this downside. What people are typically told is happening is that the credit card still 'belongs' to one spouse, but the other will be also authorized to 'use' it. While this is possible, the paperwork presented to sign often makes the other spouse jointly liable for the debt instead. I'm convinced even the bank representatives don't know they are setting up things this way and are just following a script. You have to read the paperwork to see what it does.
This is exactly where I was leading with my questions. Joint accounts might simplify the sharing of cash between household partners, and thus simplify household operations, but it complicates everything else.
I suppose a temporary convenience now is worth a very complicated situation in the future. Thus is also why we traditionally forego prenuptial agreements.
No, it's for having a shared pool of money. Both regularly deposit some amount of money into it, and it goes for shared expenses like food, house maintenance, gas...
I'm going to add that it's also really nice for budgeting. If you want 2 people to get on the same budget you have to show the benefits of the budget.
Also I don't pay 1/2 my mortgage and my wife pays the other 1/2 we pay it all together (from the one account). We actually turned down an account with Plastic because no shared accounts.
We each have an individual credit card but that's more for tracking if we are meeting our own budgeting goals. But those are still linked to the other person.
Also, joint accounts make a situation where something happens to your spouse MUCH easier to handle. If something were to happen to me I'd want my wife to still be able to pay for Daycare, Mortgage, etc for as long as our savings would allow.
This is part of why divorce is hard on so many levels. The paperwork alone is crazy.
Once a business is incorporated, it is its own legal entity and needs to have its own pool of funds that is legally separate from the owners' funds.
There would be one or more accounts held in the name of Super Secret Labs LLC and in most cases that business account would have rules about who was allowed to approve the transfer of funds out of the account, and to what limit. In many cases it may require approval from 2 account holders.
Prior to incorporation, the call on funds would typically be much lower, so it's probably going to be a bit ad-hoc, and might just use an account held by one of the founders with everyone throwing their share when needed. If you can't trust your cofounder with $2k, then don't start a business with them.
Man breaks up with his partner, and moves out of their shared home. He changes his phone number to be his new home.
Amex calls the old number, gets the old partner who is particularly vindictive and decides to answer the questions as well as he can.
When I worked in banking we had all sorts of issues about how we handled change of address with respect to relationship breakdown.
If a husband and wife share and account and share an address do you send them separate statements, or combine them? If the husband tells you he has changed address, do you assume the wife has changed too or assume that she's still at the old address? If he's on the phone, you can ask him but do you assume he's telling the truth?
If one member of a relationship chooses to change their mailing address, for security reasons, you might want to send a notice to their old address in case the change was fraudulent - but if they've changed their address because they're fleeing an abusive relationship then you can't send anything to the old address that indicates what the new address is. And just because someone at the old address raises an objection to the change that doesn't mean it was wrong, just that you need to do more investigation.
Those sorts of incidents were rare, but our procedures needed to plan for them. And in this case, the correct action would be to lock the account and escalate to a superior.