Is there a humane way of doing this? Some sort of trap so the live snails
can be emptied a long way away?

My plants are being mutilated every night, I'm managing to catch the ones
still there during the day (one planter had 14 baby snails in it!) but I
reckon there's a battalion of them that come out after dark.

I really don't want to kill or hurt them so if I can "relocate" them I'd be
happy. Failing that, is there some sort of contraption to put my pots and
things on that they can't climb?