Alright, here are my new thoughts on the situation.
I just returned from sneaking onto the Sandals Negril property to take pictures. It actually went fine... however would I do it again, NO! They didn't appear to actually have any problems with having a photographer there, so I would suggest you simply get it in writting from the WC and do it the legit way. I didn't like having to "sneak around" (there is no sneaking with a camera this size) and I couldn't bring or carry my equipment the way that I wanted to. I was constantly having to hide memory cards in case they would take them from me and of course all of the lies got old too.
In the end, like I said, the wedding went beautifully and we got great photos, but I would have your travel agent talk with the resort wedding coordinator and simply get it worked out ahead of time.