A few years back I was transiting the Med south of Nice and the Controller was having a great deal of trouble locating a UK registered aircraft, the guy in the aircraft seemed to be giving all sorts of conflicting position reports.
The controller asked me if I could try to locate the guy and put us both of to a descreet frequency to try to sort this out. The nub of the problem is that the guy did not understand the deference between VOR course and radial.
Having located the guy and passed him onto the correct controller, the French controller I was working says " you have helped me so I shall now help you" and clears me direct to my entry point into the Roma FIR, a clearance that saved a great deal of dog legging.