Thing is they joining parties without filling the requirements that the PF creater has asked for, it only takes a minute to ask the PF leader and explain there situation and give the party leader the choice of taking them along or not. If they agree and it's a disaster, they went in knowingly. It's polite to ask first, it's not when someone enters a party asking for clear experience and doesn't say anything until the party enters the content and the bonus tomes message shows up. How much of an impression do you tink that will leave when they find out who it is? Not to mention wasting peoples time.
It wont stop run buyers and those who get carried joining, but it would reduce it. Also it may have the knock on benefit of more players joining learning parties if they know they can't sneak into a farm party to get their clear. As I can imagine their thought process of being something like "Why should I spend time wiping on learning the content when I can just sneak into a farm party and get the others to do it for me?"
