...appeared excellent in June 2002. There were a bunch of Malaysian marines on the island, dressed in civilian clothes (rifles in golf club bags, funny). They arrived in seriously fast gun-toting crafts; could have been used for invasion purposes I would guess.
Bin Laden would be unwise to direct his last supporters in the area to take some divers as hostages, they'd be pretty quick dead supporters. Moreover, the US Seals are chasing these criminals all over the Celebes Sea, they should have other priorities these days than getting their hands on innocent divers - like staying alive.
I'd be more worried about petty crime / robberies in Tawau and Semporna - those are grimly looking places overrun with Indonesian refugees. Not a pretty sight. But please, do not let this deter you - keep your wits around and you'll be fine.
Enjoy!