[squidbeak]

I can't answer to the law, which besides will vary - and I reject the implication that a puerile prank is immoral. But that aside, taking it on as if there was any moral dimension, moral clarity is straightforward here:

The parasite has to answer for the material it shows its visitors.

If a butcher delivers outdated meat to nowhere, knowing his van will be hijacked, how can he possibly be blamed when the hijackers sell it to their customers?

Edited to correct can (van!)

[nephanth]

But he can. He is clearly attempting to poison someone.

[beardog]

Yeah, it is for similar reasons that you (legally) shouldn't set booby traps against burglars.

[ericpauley]

> If a butcher delivers outdated meat to nowhere, knowing his van will be hijacked, how can he possibly be blamed when the hijackers sell it to their customers?

An obvious corrolary to this is the prohibition on booby traps.