Good point. And you know what, without writing a little test app I am not 100% sure on some of these questions either. Anyway my understanding at the moment:
Paintmesh paints all surfaces with the same brush. You may find its problematic to unpaint a mesh and restore it to a previous state, though in simple terms of course you just remember how you painted it in the first place, but thats assuming you did paint it in the first place and you have not complicated matters with addmesh or copymesh both of which will consolidate surfaces.
Brushes of themselves are not sticky. You can attempt to find a surface painted with a particular brush, so I guess you could code something along those lines yourself though this raises the question of uniqueness. If two brushes have identical properties can you find surfaces painted with each. The questions just never end do they :)
Paintmesh paints all surfaces with the same brush. You may find its problematic to unpaint a mesh and restore it to a previous state, though in simple terms of course you just remember how you painted it in the first place, but thats assuming you did paint it in the first place and you have not complicated matters with addmesh or copymesh both of which will consolidate surfaces.
Brushes of themselves are not sticky. You can attempt to find a surface painted with a particular brush, so I guess you could code something along those lines yourself though this raises the question of uniqueness. If two brushes have identical properties can you find surfaces painted with each. The questions just never end do they :)