quick from wiki:
The United States Navy operates Naval Support Facility (NSF) Diego Garcia, a large naval ship and submarine support base, military air base, communications and space-tracking facility, and an anchorage for pre-positioned military supplies for regional operations aboard Military Sealift Command ships in the lagoon.[4]
To allude the U.S. Navy had no knowledge of an aircraft entering the airspace of Diego, much less for it to land, refuel and restock with ‘refreshments’ is ridiculous. If 20 were unloaded (assuming FreeSource employees) why didn't any single one of them get on a phone and place a call? or, for that matter, why didn't a pilot drop a dime? not like there's no communications links on the island...
What I see is more cat-and-mouse games from the disciples of Mohammed imo.
Diego Garcia has cellphone service GSM/Edge. Anyone on board with international roaming could have made a call/SMS message.