The whole scenario is ridiculous. The receiving player has to let the ball cross the net. They cannot be impatient and hit it before it does. However much it floats over! Without an umpire sitting over the net, or better still hawkeye to help you out, you are entering silly territory. Be patient is the answer really.
How does being patient solve anything?
In an unofficiated match, the person hitting the ball makes the call on him or herself, per the code:
From the Code: (
http://assets.usta.com/assets/1/15/2014FAC_final.2.pdf)
"19. Touches, hitting ball before it crosses net, invasion of opponent’s court, double hits, and double bounces. A player shall concede the point when:
• A ball in play touches that player;
• That player touches the net or opponent’s court while a ball is in play;
• That player hits a ball before it crosses the net;
• That player deliberately carries or double hits a ball; or
• A ball bounces more than once in that player’s court.
The opponent is not entitled to make these calls"
I've only come across one case where there was a clear violation. That's when my doubles partner clearly reached over the net to hit a volley. Based on the position of his racket you could clearly see the racket was in front of the opponent's side of the net (basically you could see the opponent's side of the net through the strings in his racket.)
Everything else with a ball coming in over the net, in most cases it's just to close to call and generally not worth making a fuss over.