[thaumasiotes]

Yes, they are printed on the bottom of checks because they are the information that allows conversion of the check into money. Yes, giving a check to someone compromises your account. You're trusting the other person to do nothing other than withdraw the amount on the check, but you're giving them enough information to withdraw whatever you have in your account.

[encoderer]

And be charged with a crime for it. That's the other part. Not just trust.