I think it is like your neighbour calling the police about you because you didn't shovel the walk until 25 hours after the snowfall instead of the 24hrs in the bylaw.
I coached a team that was eliminated from the playoffs by one point when the opposition coach called an illega. curve on one of my D who didn't score a goal all season. It is legal to call these things but I don't think it is sportmanlike. He should have pointed out the illegal pads after the game and said that if it happens again he will inform the refs.
That is my take on it.
Here's my 2 cents:
If you see an equipment violation that either:
a) is a safety concern, or
b) is impacting the outcome of the game
notify the officials at the first opportunity.
I don't like the idea of keeping an ace in the hole to call upon only if you need a power play later on. I also think players bear some responsibility to know the rules and follow them. Knowingly playing with illegal equipment is also an attempt to win by unfair means.
Go Team USA!