Toilet stops for small children (although why anyone would stand in line for an hour+ with small children is completely beyond me!) is entirely different to someone going and getting fast passes whilst other members of the party hold a position in a line.
Line cutting has to be one of the most annoying things in any park (see another current thread in this forum), and although we've seen it for ourselves many times, I've never once seen a CM enforce the rules (hopefully we've just been unlucky and they really do occasionally)
Personally, with the advent of fast passes, I can't understand why people stand in long lines anyway! Perhaps it's because we have a 3 & a 4 year old, but anything longer than 20 minutes is too long now... But I've always been a little impatient!