The doubles guy I mentioned was a sub. Our group is good, we've had four guys standing over a mark, usually an aced serve, marveling at how it shows the serve just touched the tape, 'hey, take a look at this' kind of thing.
We want to get the call right and let ourselves enjoy 'the game' playing itself out. The occasional serve or shot on the tape that leaves no mark is in.
You get some dingdong in there that starts screwing with the calls and it's a different thing altogether. The guys I play doubles with are an established group and I 'do like in Rome' with them...they're super-polite so I don't question calls. In my singles, I'll question a bad call without hesitation unless I'm killing the guy.