Ok, maybe I got pulled in by a troll on this one, but I've found a cache once (one I *didn't* log) that had an uncomfortable amount of marijuana in it. As a non-participant in such, I was offended. I would have been even more offended if my kids were with me, and I had to explain to them what it was. As it was, I simply replaced the cache and walked away.
Afterward, I started thinking about it. If some law enforcement official were to find the cache, it now has my fingerprints all over it. So I propose that any cache that contains illegal or controlled substance needs to be flagged both on the website, and with a 6-foot-tall neon sign over the cache itself, flashing "WARNING: CONTAINS DANGEROUS DRUGS!"
If you can't handle some tracts and such, just walk away. Part of the fun here is not knowing what you'll find...