As av8boy pointed out, just because you have an IFR ATC clearance from an uncontrolled (no-tower) airport does not provide any safety at the airport from anyone except other IFR traffic. There could be many VFR aircraft runing around the surface or in the pattern that ATC has no knowledge about. A good example is South Lake Tahoe. Oakland center has a remote freq at the unoccupied tower. Business jets call get thier clearance and normally get a hold for release. They are told to call when taxing for a release. They call and get their release and then question why the Cessna 182 is in the way for the runway. We tell them not our problem, they are the only IFR aircraft but it is up to them to stay away from the VFR's. This becomes a real mess when the IFR traffic does not go back to the Unicom prior to takeoff and departs rwy 36 while an aircraft is landing rwy 18 which is normal ops. It seems some pilots presume ATC is providing seperation service just like when a tower is open. Nothing could be further from the truth.