Thanks for the input but not so much use.
When you "tone" for the car a mile ahead of me - I see the signature, and the SSID frequency - so I know its not something else. I can capture it miles away on the interstate where there isn't much other interference, even with small hills, curves, trees, etc. Also a good radar detector can pick up the residual signal long before the signal is strong enough to get a bounce back to the gun - all the detector has to do is see the signal - the gun has to shoot the signal, get a bounce where much energy is lost, and the signal needs to return to the gun with enough energy for the receiver to remove the phase error and output a value.
Some cops around here don't "tone" anything - they turn it on, sit at their speed trap and surf their phone - I see them going by. My guess is there about as interested in handing out tickets as I am to get one but there boss told them to go do it. They probably only pull over the worst offenders. I pick them up at known speed traps all the time well out of their range, even around a corner or through trees - favorite hiding spots of LEO. When I come back they have someone else pulled over.
So yes, if the cop is doing their job diligently, and I am the only one on the road, and you have a crappy gas station detector, then your analysis is correct. But with any amount of traffic and a good detector, its not that simple.
Like I said, not trying to speed, just avoid the speed traps and speed signs behind the bush