If you play one up one down then they can suck it up for a night getting the luxury of not bringing a kit.
Usually the gigs I play are 4 bands with quick change overs so if gear shareing is involved it is discussed a bit first.
Cymbals, pedals, and snare are NEVER included.
It is usually kick, toms, snare stand, hat stand, cymbal stands.
Throne should be discussed. Some guys don't want to share butt sweat. Others don't care.
Pedals are a very personal item. I set mine up for MY playing and don't want to use other peoples. I also don't want someone hulk stomping mine day in and out when they cost so much.
At the end of the day, I have loaned my snare, pedals, a crash to to other guys who have forgot stuff to keep the gig going, but I don't make a point of offering it every night. This stuff is super expensive.
As far as the tom, it's not much extra work, but if you let another guy add it, hes going to have to change the set up, move the ride, change cymbal heights etc to make it work, then you have to waste all that time putting it back.