It's also regularly confused with a way of saying "I went to a school with 'progressive' (read: stupid) ideas about spelling, where the 'teachers' would say dumb shit like 'how would you spell it at home?'"
Fortunately I missed all that nonsense and regularly had classes on the correct use of and distinction between they're, their and there; two, too and to; bear and bare; should have vs should of; i.e. vs e.g., etc.