ANSA.
I am a big fan of pilot discretion. I don't think they should blindly follow TCAS. That implies that TCAS is infallible. TCAS will often ask aircraft to cross levels, which can only rarely be the best option (imho).
Have had a situation where the aircraft (AN 737 vs Southern Dash8)were fully clued up (traffic passed etc) but due to high rates climb/descent received RAs. They both (sensibly) elected to follow the clearance, confirmed verbally, and continued on. The TCAS was asking them to cross levels, which would've reduced the sep to min miss distance (600' 1nm?). Stopping at their assigned levels was the better option in this case, and I don't believe that option should be taken away.
Shades of grey, mate, shades of grey.
TCAS is a can of worms though, and needs sorting out. It certainly shouldn't be the prime seperation device between lighties and jets, a la NAS class E.