RULE #1 - If you call a RUN DEFENSE, key somebody! Options

Why?

Three Reasons:

1 - There are no penalties for incorrect run keys by the defense. You can only gain from run keying on the correct RB.

2 - Notice I said if you call RUN DEFENSE. If the offense calls a play-action pass, they will already get the benefit because you called RUN. You are not penalized twice because you RUN KEY. Now, with that said, if you call an ALL-PURPOSE along with a run key, then you will give the offense a benefit if they call play-action. To reiterate, the offense benefits from a play-action pass if you call RUN DEFENSE or if you RUN-KEY with an ALL-PURPOSE only.

3 - Wayne (the creator) told me so.... :-)

Hope this helps!
Mark Miller