As I've moved up, I see less and less warm-up weirdness.
Even at 4.0, however, there are a lot of people who cannot seem to hit the ball back to you. I am starting to think that these are people who really do have control issues and it is not gamesmanship.
Lately, I have noticed that if someone cannot feed a decent lob in warm-up, this means they are not a lobber and I can feel safe draping myself on the net until they show me a lob.
I have noticed that some people struggle in warm-up to hit the ball DTL (especially right-handers in the ad court). This is license for me to leave a little earlier on poaches because they clearly struggle with directional control.
So yeah, it's annoying. In your case, the guy probably just didn't know better. In my case, these players are leaving little clues on how to play them.
-- Random Error Generator, Version 4.0
-- Master Moonballer