I get honked at a couple times a week for not turning right on red at a certain intersection. The reason I don't is because it's unsafe. Yes, it would be legal, but in this case it's not a good idea.
The road I would be turning on to is very narrow, and goes downhill as it approaches the intersection. The cars coming from the right are coming to a T, so the ones turning left don't have to worry about oncoming traffic. The net effect of all that is the they start drifting into the lane I would be in as they start their turn. You'd have to be insane to turn right on red if there are cars coming down the hill, unless you're on a motorcycle and can hug the curb as you do it.
I won't do it at other intersections if I can't see far enough to know if it's very, very clear. I also won't do it where I would be turning onto a multilane road if only the right lane is clear. I've seen too many people who weave in and out of lanes, and I won't assume they will think to stay out of the right lane because someone might turn right on red.