I know a crocs fanatic, been walking with him and he wears them almost everywhere. When we went to gaping gill I only just managed to talk him out of wearing his crocs saying he happily uses them with a pantin attached, ascending trees. Despite me bringing my son's wellies for him to borrow (same size, my son has big feet) he insisted on wearing some sort of canoeing wet socks with "grippy" rubber dots instead, which meant we couldn't cross mud hall as he was "ice skating" and going ar5e over tip as soon as we got near the mud. I think he'll never wear wellies from now till the day he dies.
To be fair to him, until that point these tread less canoe things or crocs would've been ok for him while it was still rock. It takes all sorts to make the world go round and the crocs fanatics are certainly different/special people.