What would you do?

[Nevadaref]

Originally Posted by Mregor

I got nothing. Intent has no bearing unless there is a foul. Sounds like you aren't even sure there was contact. If I thought he tried to trip, I'd talk to coach and let him/her know if he had succeeded, he would be in the showers, but you can't penalize on intent alone.

Your response is inaccurate.
If A1 attempts to strike B1 with his fist or elbow during a live ball, but B1 is able to duck or dodge the intended blow, A1 still committed a foul and the official has the authority to penalize it.