What kind of massive retaliation? I met with similar incredulity way back in 2010 when we were discussing Cold Start and fellow Pakistani members were emphasizing the deployment of nuclear weapons at a tactical level. I had only one answer for that - no nuclear weapon is ever a tactical weapon, they may be used at a tactical level but then they become strategic. And India considers any kind of CBRN deployment be it tactical or strategic, counter force or counter value, as a strategic deployment and will respond massively to inflict 'unacceptable' damage. That, in effect, puts to rest the nuclear dimension until and unless over a couple of Islamists and convicts the Pakistani establishment is ready to risk an all out war with potentially uncontrollable comsequences.
The same has been amply clarified by Shyam Saran .... in 2013.
Now coming back, since you are from a services background, you are aware of UAVs of both sides crossing the LC frequently for recce .... how many incidents of shooting them down have occurred till date?