Not that the FCC gives a damn, but as a contester I do, a little bit.
The WM3O contest exchange example above is very accurate for many contest contacts.
So is this kind of exchange:
DX: QRZ DE PJ4T
DX: TU 599KW
DX: TU QRZ?
There was never a real exchange of callsigns anywhere in there. Happens all the time.