Hi Psyklon, yes it could well be. I chose caps purely because it is the one that is more familiar to me. Rather like the case / cash debate from the same crossword, it is down to individual preference and await the published solution.
Like it Aljanon! I think you are right. Chambers has Dunces Caps, refering to it as "a conical hat formerly worn at school to indicate stupidity". So that's why my head is pointed!