FWIW, NTRPolice, I disagree that it is a bad idea to warn your partner of a short lob.
I have had partners explicitly ask me to warn them of short lobs. I give the warning if I think of it, and I appreciate it when they do it for me.
Yes, giving a warning runs the microscopic risk that some opponent someday might claim hindrance and claim the point. Failing to give a warning, however, risks that (1) your net player will be surprised by a short lob, and (2) that partner will dislike playing with you because you throw up short lobs but won't warn.
I think if we took a show of hands of how many people here have ever had an opponent claim hindrance if they say "Short" or "Watch it" or "Watch out" when they hit a short lob, very few people would say this happens.
I think it happens even less at the higher levels because players know that giving a warning is quite common.
I dislike it when I hit the ball out but a rule is a rule. If I hit out, I lose the point.
Whether or not the penaltY is called frequently the rule is there for good reason. Breaking it is, well, cheating, and you're basically putting your opponent in the unpleasant position of having to supervise YOUR behavior and adherence to the rules. And you're hoping they'll feel uncomfortable enough to not enforce the rule...