These antics are usually reserved for the red band trailers -- ads with R-rated content from the R-rated movies they advertise. Many theater chains won't even play red band trailers partly in fear that a mixed-up projectionist might place one on a kiddie movie and face the wrath of an auditorium full of angry parents. I have distinct memories of working as a theater manager when the trailers for Independence Day hit and the three words "aw, hell no" that Will Smith utters in the ad were so offensive to sensitive customers that we actually had to pull them from our prints.
I'm not a prude about it (I'm actually pretty pumped to see Get Him to the Greek, as I loved Forgetting Sarah Marshall), but how in the world are things like rectal drug-smuggling and ejaculate sneaking through with a green band? They're just on the cusp of what's considered unacceptable for prime time television, but I truly sympathize with any theater manager out there who has to deal with a squeaky wheel customer, upset over the content of a trailer.
Maybe it's time for a yellow band trailer -- something in-between the green and the red that will let audiences (and the exhibitors) know that the content of the ad may be too much for a family going to see something like Avatar, which is a relatively tame PG-13 (as opposed to a tougher PG-13, like The Lovely Bones for example). I know that's what the red band is supposed to be for, but as the green bands get dirtier, I fear for my brothers and sisters in theater management. Nobody likes dealing with an angry customer.