Ohelpohnoitsa I do, actually, although it's only homework, not exam papers! I've also started to refuse to mark anything where capital letters aren't used (correctly). Only at A-Level, mind! Haven't heard the 'why' instead 'what' yet!
A lot of youngsters around here have started saying "why...... for", as in "why have you done that for". That annoys me. Not as much as marking hundreds of exam papers where A Level students repeatedly write "This business COULD OF borrowed money from....." could of, should of, would of...... I HATE IT. IT MAKES ME WISH I COULD TAKE MARKS OFF.