I won't blindly respond to an "A.T.P.A." request either.
If the other aircraft's position report indicates that I'm not going to be a factor, I'll keep my trap shut. If it appears that we are going to need to be doing some coordinating, then I'll self-announce. Funny thing is that those are the exact same things that I would do if pro-airliner-pilot hadn't added the unneccesary "A.T.P.A." call. So he just wasted airtime for nothing.
Unsafe for me not to answer? Hardly. I can use my judgement and determine whether or not it is important for the other aircraft to know my position. I don't have to answer the call, and in many instances it may be unsafe for me to speak up. What if there is an aircraft that is a factor, and my response steps all over his? Now pro-airliner-pilot knows about me, who is not a factor, but is clueless about the the bug-smasher that's turning a 1/2 mile final right in front of him.
Like I said before, I'll stick to standard phraseology and recommended practices. The AIM isn't just an off-the-cuff collection of pilot aphorisms. There are reasons for the stuff that's in there, and it strikes me as rather arrogant to assume that we know more about the topic than the guys that put it together.