Nobody is always right. New things about old songs keep turning up all the time, and previous judgements often have to be modified. I try to stick to facts, but once in a while I can't find any and have to rely on what somebody else said who didn't document the source of his/her information (I usually qoute them and give the souce of the quote, so if it proves wrong it's not my fault). I'm very critical in my choice of 'experts' when it comes to this kind of thing. My feeling in general is that professionals try to get some valid information, but often aren't very critical about what they pass on, and some of it is nonsense (though it usually makes a good story). It's also amazing how often when somebody tries to paraphrase what someone else said they get it completely screwed up.