I dont see why sellers would be overly wary to turn you down to be honest. The funds are received before the item is sent out, so they are in the clear as far as financially covering their asses. I could see if they're skeptical because your fresh to the forum, and cant confirm your true identity on if you have a stolen/ripped off PAL or if you are who you say you are when you supply your information for proving your PAL... but even then calling the CFC and verifying you are you, and the address the gun is being shipped to is actually the one registered to the PAL.
Ive never had a problem selling to newbies. Buying, I definitely am a little more diligent than normal. But as with any online interactions, it's always a risk.