I appreciate what your saying. We did debate on what to do and came to the decision to try to reunite it with it's owner through online media. Our decision was based on the following - no-one had come towards us on our approach to the summit (and would therefore be ahead of us if still in the area), we were on the summit for around 15-20mins and were clearly the only people in the vicinity, if they were ahead of us we would meet them if they had turned back and they would see us carrying it and as it was late in the day it may have been sitting there for some time.
There is nothing of any real value in the bag, in fact it's virtually empty with no name or address. If this was the wrong decision it was made with the best of intentions.