Well, then you have an R-antiphoton containing negative energy which is going to end up hitting something at random and causing an unexpected phenomenon.

If you don't like that, I think the ball is in your court to propose an alternative optical model of vampirism which has fewer problems with conservation of energy :-)

I think it's high time we stopped faffing about with the theoretical physicists and started taking some measurements off an actual vampire in the optics lab.