Drjones, yes, there is. What trainers often do is create a reference point for the index finger. This is often done with skateboard tape.
"Hey, my finger hurts."
"You're doing it right then!"
Rule #3, the Golden Rule, is the most critical rule of them all as in some scenarios, counter-ambush, team tactics, et al, a #2 violation cannot be avoided. Train hard, mopar!!!
Your reply confuses me.
There IS something wrong with teaching a newbie that the trigger is "bad"?
And the scenario you describe doesn't make sense; inflicting pain when it is being done right?