mine got stuck together and i spent it by mistake
I know someone who has received gimmicked coins as change twice within the last few years. I would think that the odds are slim to nil of ever receiving one, let alone several and I never have gotten one back as change; but I always check the weight and sound of coins I receive as change. ...You never know when you'll get a free magic utility item worth far more than your pocket change as a result of some other magician's poor and/or otherwise accidental prop management.
I have to admit, that would be awesome to receive something like that free. Imagine though, how careless are you if you actually spend a gimmicked coin?