Dilly,
FCs on routine sorties validate and verify. I'm pretty sure that AWACS guys validate and verify their normal squawks too. However, on big exercises where there may be 10 - 30+ ac on freq this just isn't practical so those NATO exercise squawks ending in 00 are usually used.
PS: It is possible to do radar handovers to AWACS, but involves a lot of radios!
Regards, ADIS