This is probably a stupid thing to post a response to, but I've done a lot of stupid things today so - what's one more..

Obviously, both of these methods will work at some point or another but consider the following before you decide to go ahead and see for yourself:

The missing money will come out of said person's pay. (achan points out this is illegal. I counter-point out it still happens, especially in a smaller business. As Excalibre says, it can also mean losing the job entirely.)It is not so simple as saying "It's not their money anyway." "So what?", you say, "It's just x dollars, and next time they won't be so stupid." A lot of times people are working these shit jobs because if they don't, they can't buy food. No, not even food for their hungry baby. The x dollars you just lost them could be a big deal to them. Maybe they were having an off day, maybe they are too trusting. It really doesn't matter.

I just felt this deserved a little elaboration. Just because someone isn't as bright as you, or is perhaps having an off day, does not mean you deserve their money.

More succinctly, it's a real dick move.