If someone wanted to use my rig, I'd say "do you know about gainstaging" ?
If they said yes, I'd say "yes, go ahead please set it up for me"
Yep, you've gotta ask, the only shared gigs I've done in the last few years had 15min slots to change drums and amps, the band had to have everything ready with an up ramp and a down ramp, so it's not been an issue for me.