Right turns beyond channelized right turn
A few of us have recently been discussing whether a certain type of turn is legal or not, with differing opinions. I'm hoping someone here might be able to settle the matter.
There are many intersections with a channelized right turn lane, where drivers turning right are separated by a small island from through and/or left turning traffic. Here's an example of one of these intersections:
Obviously, if someone was planning to turn right, they would use the channel at the far right. Now, what if a driver pulled up to the stop line planning to go straight through the intersection, but then changed their mind and wanted to make a right turn. Would it be legal to do so? Does the presence of the channelized right turn lane imply that right turns beyond that point are illegal?
I've seen a few intersections with signage or lane markings explicitly prohibiting right turns in such a situation (or at least implicitly, like an "only straight through" arrow), but most don't have any signage or lane markings prohibiting it. Personally, I always thought it was legal to make a right turn at the intersection. Am I wrong?