Usually the match copy will state if brass picking is allowed or not.
I’ve even been to matches where is wasn’t allowed but I asked the MD or RM and was told at lunch or after the match is okay.
Mostly it’s done to maximize throughput; picking can slow down the flow of shooters (larger shoots).
As a guy who used to shoot lots of 45 I would suggest to be your own advocate; ask beforehand.
If it’s going to be gone, so be it or don’t shoot.
Most club shoots I’ve been to and all the ones I put on allow for it because we have fewer shooters and have the time, if guys want their brass they can grab it as we score/tape and reset (plus a second or two).
Or you shoot 9 and don’t give a sh@#, lol...
Only been to one club shoot that ticked me off in regards to brass...we were going to collect up the brass at the end of the day but this guy stopped in, shot the breeze with us and then unknown to me picked the stages clean and left (while the shoot was still on)...it was a 3gun so I kinda wanted my 223 brass...It wasn’t that the brass was special, I just thought it was a douche move.
Nobody got their brass, lol...