ESP and others; You see too many James Bond movies.
The purpose of an interception of a loss of comm of an airliner , in Europe at least , is to VEFIFY , not to shoot it down.
My point is that once you have re-established comms and it is obviously a frequency change problem, and everything is as before :,guys on correct freqs, on correct track, why not call off the interception? What is an interception going to achieve more ?