The constant replies are missing the forest for the trees. The issue is not the blindness ruling. The issue is a PC using a spur-of-the-moment stunt and turning it into a constant battle tactic which they are not spending resources to use.
IMO the issue is a clash of a story-driven cinematic style with a simulationist style. IMO the problem is solved by the DM first coming to terms with what kind of game he wants to run, and then communicating that to the players. If a DM is running a story game and makes decisions on the fly based on what he thinks would be cool in the moment then he can't expect those rulings to hold up to simulationist examination.
Perhaps he needs to explain to players that the rules are a vehicle for telling an interesting story and not a simulation-contract of elements that the PCs can play with independant of the preferences of the DM. Or, he sticks with the simulationist contract and makes up rules for a bag of flour that fall within reasonable parameters (and therefore warriors continue to carry around swords as weapons rather than bags of flour).