I never said I was in Glass G
and sorry but I have every right to question a controllers clearance...
I was being a wiseguy, in the US, the only uncontrolled airspace is Class G, granted class E may be minimally controlled, well, the less restrictive at times, it still belongs to some ATC facility, normally a center, but not always.
And yes, you have every right to question a controller's clearance. And tgrayson brought up a great point, in the "unless it breaks a regulation" (CFR or Company I'd probably add) that is why "Unable" is in the phraseology, granted you make get something like, "Roger SAC(Some Aviation Company)XXXX, turn left/right XXX, number 99 for landing" not always, from what I have see, most controllers seem to be understanding when you tell them unable, granted I'm a FSSEPP with a little under 70 hours, so I haven't dealt with a lot of controllers outside of my ZLA bubble, and as a VFR guy, I don't deal with them much.
Back to the "legality" thingy-ma-bobber, the reason I say a CFR, clearily if it is going to give you a trip to the local FSDO, don't do it, "Unable to turn left heading to approach heading 360 from heading 330" (because of have to over bank the aircraft) I know I know, that is what a PT is there for, but you get my example, I hope. If the controller goes to the chief's office because of it, TDB. It isn't your responsiblity to comply to the 7110.65, last time I check, it is the controllers job.
But I will say this, and I think this was the result of a prior fight/argument on this forum. We, the NAS/Pilots and Controllers/etc., are a co-dependant bunch of aviation lovers, but as individuals, some of us have a long memory when we get burned, regardless of who's fault it is.