Michaelmas is a
sensitive bird breeding area, amongst other things
Interesting there is also a reference to "Fly neighbourly" on that website... just in case you thought you were missing out on some credit.
There are literally two other cays (three if you still count Upolo) within a couple of minutes flight time from Michaelmas, plus a bunch of others a little further away. So why did your mate think he was entitled to disregard the rules, given ignorance is not a valid defence?