It's a question of standardisation, and in the specific example given, I wait until clear before any config change...
If the pilot can give a reason why he does any particular thing, and it's a good one, and you can't find some argument against it - then so be it. If the "basic technique" being used is flawed or dangerous then jumping up and down should ensue.
One example I heard of was of a student poking a grass stem into the static vent to check it was clear. As it transpires, the student's instructor's INSTRUCTOR had done it ONCE, some years before, whilst casually chatting (for what reason I don't know) and the "habit" or "basic procedure" had carried through.
In the case that it is a safety issue then logically explaining why something should be done in a particular way without going apesh!t should be enough to change their ways, and if it doesn't - maybe the pilot should reconsider their involvement with flying.