I always watch the cutscenes the first time I see them, they are interesting to me.
I understand that joebob has run the instance 20 times and doesn't need to see it again, but he should respect that everyone else may not have.
When I join a FP for the first time, I tell the group flat out that its my first time and I'm watching the cutscenes. Either they accept it then and there, or they find a differnet healer. If I've run it before I will skip the cutscenese in order to speed things up, but I dont' demand everyone else does too (it may be thier first time after all).
TLDR; Tell the group you will be watching the CS at the start of the group, if they don't like it find another group. It will save you a headache and a poor experience.