The diving conditions here are very different from those you'll find on the Upper Keys (which I know well), and indeed different from those encountered in many areas of the Red Sea. Although it isn't always the case, I'd say it is generally desirable here for a guide to accompany divers. For example, I have never seen really deep water at the Keys, whereas everywhere you dive in Belize (assuming you're not inside the Barrier Reef) there is extremely deep water nearby. From any of the mooring buoys off Ambergris Caye there is water several thousand feet deep within a short swim. You may be a competent diver but I can assure you that we get many who are not competent, and these people need to be monitored and on occasion controlled.
You'll find that at the better dive centres, once you have proven your navigational and seamanship abilities over several dives, you will be allowed a lot of slack. We don't like "follow my leader" dives any more than you do. If that hasn't happened, either you haven't chosen the right operator or your diving hasn't been seen to be up to the level you suggest. We don't like losing divers - it doesn't look good on our records.
May I ask how you would conduct yourself if you were diving without a guide (who may or may not be a DM) in the two cases of a static moored boat and a boat that follows the divers? How would you ensure you found the boat, and the boat found you? How would you ascend safely in variable sea conditions? Are you accustomed to using a DSMB? And are your navigational skills good enough that you can guarantee that you always know where you are in unfamiliar surroundings, and that you can always find a moored boat? Actually, how many dives do you have, and what level of certification have you reached?
We dove with Splash the last day, and it was a two-tank dive with an hour boat ride each way. Their boat did not have a head, but they took us to an island that had bathrooms, which was very cool. 
