First of all, I grew up in Kota Kinabalu and have family in Sabah, so I hear things about stuffs around the state. Semporna is a very gray area, you have the pirates, the illegal immigrants, the rich that exploit the local etc. The rich would pay under table money to get land in the area, set up dive resorts while do not run the dive operation to keep environmental issue in priority, hence as long as divers are coming, they don't care much what the divers do.
Seconds, there are still a lot of bomb fishing activities that the authorities can't get it under control. You know how the bomb fishing take place? A small boat would go to the area, check the surrounding to make sure no coast guard around, then drop water bottle filled with explosive, once the bottle hit bottom, it explode (sound like some one fart in the water by the way), blast the reef and the fish float to the surface. The guy in the small boat will call a bigger boat to come and pick up the dead fish with nets. These illegal bomb fishers could be the local, or people from the Philippines, because Sipadan is just that close to the countries coast line that the coast guard can't do anything once the pirate/illegal fish operator cross the country line to the other side.
Last, there are certain nationality of divers are quite hardcore underwater photographers. I'm not going to name the country, but once I got mix into a boat full of divers. 7 out of 10 people have dSLR, and they are a group of divers from that country. Now, if you ever been to some tourist area, you probably see a full bus of tourist get unloaded, almost everybody have a dSLR hanging around their neck. Those are the group of people I refer to. Just because they have hardcore underwater camera and housing, doesn't make them good underwater photographers, and these group of people tends to be those that could cause problem as they're loud and obnoxious, I have seen divemasters roll their eyes when deal with these nationality of people.
I hate to say this, if the ban become effective, they will not get my business even though I like to support my home state as much as possible.