True that statement too. Nothing is impossible. There is always the slightest chance of anything to occur! I'm pretty sure If I got another jar or two to go in with my 18"er right now it would be fine. I think I have one of the nicest jar here in MFK... 
my snail launched onto a guppy i had once and ate it.. it was like slow motion as i watched it float in a direct line across the tank and then bam a fish swam into it and the snail moved onto its head and suffocated it..