I think this would be a revelation if it could be done.
I think those that dont have a location , and you have to actively not fill that bit in when joining, are paranoid that somehow, even with a weird forum name, and a location like Yorkshire, that all the BC hackers, of which there are over 30,000, are still going to discover your real name, your address, and steal your identity.
Why people dont put relevant info in for sale stuff is just as mysterious. Perhaps they deliberately leave out useful info so that they get a lot more replies asking for stuff that they have left out, so it looks like more people are interested in their item