in regards to heavies, I can only assume that they have pre-programmed their STARs into their FMC even before departure, would ATC change this for any reason ?
They don't, or they shouldn't, until they get cleared for the STAR. Then it gets loaded into the FMS flight plan and off the jet goes.
I heard on one occasion a QF A330 (I assume with datalink) being growled at by ATC because TAAATS had detected that the ATC cleared route no longer matches the FMS route, since the crew had "preloaded" the STAR they were expecting.
