The problem isn't with the underarm serve.
The problem is that in tennis there is no clear rule about when the point starts.
I think once a point is underway then anything goes.
But, I think it's gamesmanship to fake the start of the point.
This is all solved very easily.
We need a rule like in Table Tennis where once the ball leaves the server’s hand it is in play, and so counts as the receiver’s point if the ball is missed or mis-hit.
Once you step onto the line and toss the ball, the point is on. And then feel free to serve underarm, overarm, fake overarm and hit it underarm, whatever.
But you have to hit it, or else lose the point.
This rule also gets rid of endless ball bouncing before the serve, and multiple tosses.
The problem is that in tennis there is no clear rule about when the point starts.
I think once a point is underway then anything goes.
But, I think it's gamesmanship to fake the start of the point.
This is all solved very easily.
We need a rule like in Table Tennis where once the ball leaves the server’s hand it is in play, and so counts as the receiver’s point if the ball is missed or mis-hit.
Once you step onto the line and toss the ball, the point is on. And then feel free to serve underarm, overarm, fake overarm and hit it underarm, whatever.
But you have to hit it, or else lose the point.
This rule also gets rid of endless ball bouncing before the serve, and multiple tosses.