People arriving late doesn't bother me because they're not getting any extra time: when the test ends is when the test ends and if people aren't finished, too bad so sad.
In Texas, I had a Micro instructor that told us on the first day of class that he locked the door once class began and if you were late, you weren't allowed in, period. No excuses, no pleading, you could bang on the door all 90 minutes: you were not getting in. His reputation for doing just that to students who were late had preceeded him, so no one dared tempt fate and risk being late.
What DOES bother me is when they don't turn their cell phones off. During every test, at least one person's bag is ringing or buzzing...
repeatedly