Dabbing ethics?

Dabbing normally means that a boulderer has touched the ground or the spotter in a swing. The general ethics says that a dab means an invalid ascent no matter how small such dab was. The problem is of course that if we start to say that minimalistic dabs are OK, it is impossible to draw the line. In theory, also the chalk bag may dab sometimes it could make a difference also meaning that such dab should be considered as an invalid ascent. However, if get deeper into the case, a hand or a chalk bag that touches the ground during chalking, like in the picture, or even a friend holding up a chalk bag is should not normally invalid the ascent, although such situations should be avoided. Surely, the purest ethics should only be used for the ascents that make headlines. If you, as a spotter, make a mistake by which your friend just slightly dabs you during a swing for a 6A personal best, just keep smiling. If it is an 8A, you might instead say that you do not know and claim that it is up to the climber to make the call.