I'm not saying it's a bad thing to do, a sq, just that it would only help in a small proportion of cases. As to the chances of interception, the main factor there is WHICH FIR. Some states (France) are very quick to give their boys some practice. Others (Switzerland) famously couldn't produce an interceptor even for a real hijack!
The UK CAA want to solve this issue punitively with unlimited fines for pilots. Interestingly there's no mention of any sanction for controllers who cause a loss of communication.