This only works well if the parties have equal access to that kind of cash. Otherwise you might get into a situation where the richer founder can just decide to buy the other founder out at a price which is unfair but still beyond their cash means.

That assumes that the founders have enough intimate knowledge of the other founders personal financial situation. They clearly risk becoming a victim of it them if the other founder can find enough money.

If a company is clearly worth more than the offer, finding outside investment or even traditional financing through the bank shouldn't pose that much of an issue.

With enough time, the other founder can find outside investment.

> Catch is that if you invoke that the other party can switch it around and demand that you accept that pay for your share.

I'm kinda curious how the low-level details of that work out. Do you have some sort of 3rd-party service which temporarily holds one founder's offer and gives the other founder N days to make a decision? Or is there some other mechanism to prevent the founder initiating a buy out from backing out ("no you see, I wasn't actually serious about buying you out!").

The mechanism is triggered by one founder making a clear statement, usually in writing, that they want to trigger it. From that moment on, they are bound to it.

Apart from invoking it in writing, I think such manoeuvres go through a lawyer, which a court will usually accept them as stating the truth about when an offer was send and received. I'm also sure the clause have some text about how long the other founder has to answer and how long they have to come up with the money if they decide to switch it around.

It's called a 'Shotgun clause'.