I like the idea of teams playing in different camo, most airsofters have multiple sets, I've now got DPM, DDPM and working on MTP. This is a main tactic for milsim but I don't see why it couldn't be applied fairly easily to any normal skirmish day.
I think if I was running games I'd first sort people into main colours, mostly tan/MTP/desert kit vs mostly darker green/woodland, then put people in black on whichever team is short. This would be kit predominantly, ignoring rigs etc as they are expensive and even if I had 2 I wouldn't bring both. If you needed maybe ask regulars to turn up in one set but bring the other. I do most of the time anyway just incase. If you are really desperate having a few spare sets knocking around, like rental kit or some tape for emergencies.
Some sites even ask people to book in advance, again I wouldn't mind booking in advance and picking a side.
I think if there was a rough greenish vs tanish game you could do away with armbands/tape.
Failing that we used something called a brassard in cadets, I couldn't see why there couldn't be woodland vs desert, they shouldn't be too expensive to buy or make even, everyone gets 2 one for each shoulder. Attaching them to the top of the arm would be the challenge, but a bit of string/paracord could work.