Ive seen noticibly more warps over the last tour or so. However, here's my take on why you see warps when you close in on someone as you explain. I dont think its cheating, if you can come up with a cheat to do that then you may as well do a more effective one than just a little dance around. People think its someone pulling the plug, but that would just end up with them appearing to fly in a perfectly straight line until the eventually vanish and disco. The warping all over the screen IMO are UDP packets arriving out of order from which they were sent due to the nature of IP and UDP and network congestition/time-outs etc or other reasons.
As you get closer to another aircraft i suspect their computer (AH application) starts sending more packets to attempt to improve the fidelity of movement that you see. This is an optimisation made by HTC so that you dont have to always send the high-fidelity data for every aircraft you see (some will be well out of guns range). Eg at a distance you can get away with sending fewer updates to keep everyone in sync, but as an aircraft gets closer their computer starts sending the full complement of data so that you get better and smoother movement and more accurate position data.
Now let us suppose that either you or the other players computer has some network issues and some packets are lost, some get out of order etc. At the very point when your closing into guns range, you are also recieving a flood of UDP data from the players computer you are close to. Now with this flood of packets all scrambing across the internet (at the most critical of moments), its not a suprise that in some conditions some of them arrive out of order or just get lost - espcially if theres a dodgy connection or congestion. This would explain the pattern you see when you close into guns range they start warpin all over the show.
My point is, in short, that if someone is going to warp due to dodgey network etc, its more than likely going manifest itself when you are very close. This is due to, in my opinion, on optimisations the game makes (smoothing code) and has nothing to do with the opponent cheating or inducing warps on demand.