Uke,
I wasn't suggesting that you were suggesting... well, you know what I mean!
What is and isn't collected is a matter of individual choice, just as what is sung for the collector is. Collectors, particularly those working in their leisure time, quite often have to plan carefully what they are aiming to collect.
Personally when we were working with singers we tended to record everything, though that was modified by the fact that our time was limited and (particularly with Travellers who were quite likely not to be around for too long), occasionally we had to make a choice as to what to concentrate on. This can be risky, as was demonstrated by a friend who was recording an elderly singer with a large repertoire of songs and ballads who kept saying "Do you know 'The Old Armchair?" The collector kept pushing it down the list until the singer finally insisted and began, "Knight William sat in his old armchair", the only version of Child 253 to have turned up in Ireland.
There are songs (and information) we have been given, particularly by Travellers, which we have been asked not to use, one song we were given by several singers, about an arranged marriage, we were asked not to make public as the couple were still alive at the time.
I have never heard of a case where a song was not recorded in order that it should remain solely the possession of the singer; East Anglian singer, Walter Pardon summed it up for us when he told us "They're not my songs, they're everybodys".
Jim Carroll