I've squashed a few snails here in Portugal. It was an accident every time and I only knew when I heard the sound of their shells crunching under my boot. They like to come out in the dark after it rains. The first time I heard the crunch I didn't know it was a snail. I only figured it out after seeing them squashed on the sidewalk a few days later, victims of someone else's boot. At least I'm not the only one. Maybe the snails think they are safe because they are so huge. They think that surely there is no way we would miss them. Unfortunately our eyes are much too high off the ground for proper snail safety.