It's worth noting that civil forfeiture doesn't just apply to cash. It can be (and has been) used against bank accounts or pretty much any property you can own. For example, here's a case where the government tried to seize $115,000 from a couple's bank accounts (without charging them with a crime): http://blogs.wsj.com/law/2015/05/08/after-seizing-couples-ba...
Which is an awful thing to say about the police, but is probably reasonable advice to give.