In some classical texts GV 4 was actually contraindicated for both needling and moxibustion, so I wouldn't be surprised to see that cupping would be contraindicated as well. I think the general idea with GV 4 is the points strong yang tonifying properties (you wouldn't want to release yang in general - with yang being our deeper energy/force/qi/jing, not excess heat or fire). It is also one of the three energy gates in qigong/martial arts theory - along with those in the vicinity of GV 1 and UB 9 so releasing energy there could in theory systematically release qi to unexpected degrees. GV 17 was one of the first points I thought of when you posed the question for much the same reason as it is a strong energy gate controlling communication between the head and the body. It is worth noting that, GV 17 in some classical texts was another point that was contraindicated for both needling and moxibustion - so again cupping would follow there.
Unfortunately, I'm unaware of any classical quotations that clearly support these contraindications, but I'm far from a classical scholar so perhaps others who are more gifted with such education will chime in.