Along with my above post I found an exerpt from the BASIC AIR TRAFFIC MANUAL (BATM). A reference training manula used back in the 80's by the FAA in instructing newly hired air traffic controllers.
Qoute " A clearence issued by ATC is predicated on known traffic and physical airport conditions. An ATC clearence is an authorization by air traffic control, for purposes of preventing collision between known aircraft, for an aircraft to proceed under specified conditions within controlled airspace. It is not an authorization for a pilot to deviate from any rule or regulation; neither is it permission to conduct unsafe aircraft operations. FAR 91.3(a) states: The pilot in command of an aircraft is directly responsible for, and is the final authority as to, the operation of that aircraft. If ATC issues a clearence that would casuse a pilot to deviate from a rule or regulation, or in the pilot's opinion, would place the aircraft in jeopardy, it is the pilots responsibility to request an amended clearence. End Qoute.
This paragragh is mostly used by the FAA in cases against them, A get out of jail free card if you will.
A case involving TWA flight 514 in Dullas in 1974. The NTSB found that ATC was in error, but the pilots were ultimitly blamed because of the above paragraph.
ATC has no control on how someone controls their aircaft.