<<Lastly, in the event of confusion ATC can request a pilot to use any callsign they choose but it doesn't happen too often>>
Which reminds me of the old tale of a callsign confusion where the controller in question told one of the pilots that from now on he would be known as "Bob"... just after the Blackadder series was fresh out I believe. Apparently the pilot was a bit of a stick in the mud and didn't see the funny side.
Cheers,
N
"Keep smiling, it makes people wonder what you're up to..."