The secret here is to read back all direct clearances to the field as "pretty much." For example, "XXX321, Cleared direct Dodge City."
The appropriate response is "XXX321, cleared pretty much dodge." This may also be supplemented, or exchanged with "more or less," or the less-desirable, "generally." When a later controller asks if you were cleared direct XXX airport or WONSA, you can say "I heard we were generally cleared pretty much XXX, more or less, that okay with you?"
A quick visit to the pilot-controller glossary will reveal that the proper controller response is "Roger, whatever." If the controller gets upset, makes threats, or tells you anything resembling "no," then it's best to just do what he says, so nobody gets hurt.
This works the same for altitude assignments. Always preface an altitude readback with "about." Controllers love that. "XXX, PD to about two three zero." "Left heading about two seventy, climb and maintain about three five zero, more or less."
You get the idea. Never commit to anything. Also, be certain to answer queries with questions. "XXX, say assigned altitude."
The appropriate response is "XXX, what altitude do you think we were assigned," or the more personal, "how do you feel about this altitude?"
When frequency congestion isn't an issue, an intellectual discussion on the matter is also appropriate. "XXX, say assigned altitude."
"XXX, what does assigned really mean, and how does it relate to the bigger question; why are we here?"
During especially heavy frequency congestion, controllers prefer crisp, quick responses. "XXX, say assigned altitude."
"XXX, Assigned Altitude."
On those rare occasions that any of these approved tactics don't work, you can always just turn off the transponder. Then, in a foriegn accent, quickly call the controller on the same frequency and say "Hockatok control, Wunderbar Six Tree Tree Niner ist peeking up ana Ee, El, Tee, und sees a rahtha largish bowl of fiher duwn beelow." Then land, before the jig is up.
Or, you could just proceed to the destination, and make your request for any deviations the old fashioned way.
