So how will the boys enforcing the No Fly Zone tell the difference between a MiG23 operated by the Rebels from that operated by Gadaffi's Forces?
Perhaps...
A bloke behind a screen takes note of which airfield they take-off from and gives them a suitable track id...
A different bloke, called 'Bob', walks up to the Rebels and gives them a sheet of paper with squawks and times for that day...
Another bloke looks at a different screen / radio to monitor what the different tracks are up to...
All the other chaps/chapesses train regularly how to differentiate between friendly tracks and not so friendly tracks...
Even the average USAF F-16 driver knows that there is a high probability that he/she may end up fighting an adversary one day in a near identical F-16 to their own, such is the way of the modern world.