Wow, these are funny stories. I've not had problems of this nature as I don't usually have my letter keys broadcasting, just the buttons that are bound to actionbars.

The worst I've ever had was while testing some macros. I was playing my warlocks, Vidamorte and Mortevida, and having played with my actionbar swapping macro I spammed it to see if it worked...

Mortevida says: swapactionbar 1 2
Mortevida says: swapactionbar 1 2
Mortevida says: swapactionbar 1 2
Mortevida says: swapactionbar 1 2
Mortevida says: swapactionbar 1 2
Mortevida says: swapactionbar 1 2
Mortevida says: swapactionbar 1 2
Mortevida says: swapactionbar 1 2
Mortevida says: swapactionbar 1 2
Mortevida says: swapactionbar 1 2
Mortevida says: swapactionbar 1 2
Mortevida says: swapactionbar 1 2
Someguy says: 0_o
Otherdude says: What the?
Vidamorte says: Argh! Bad macro!!

Not nearly as comical as your stories, but awkward nonetheless. This was right in front of the IF bank too :S