sorry to post an evil bands question, but i cannot find the relevant ruling. if both players control creatures with bands, who will assign combat damage? it discusses if the attacker or blocker has bands they assign damage, but it doesnt say who assigns if both players do.
feel free to delete it if bands is too annoying to think about.
It's not that complex...
Damage done to a band is allocated by the controlling player. So if band1 blocks band2, band1's controller allocates the damage done to it, and band2's controller allocates the damage done to it.