P2P isn't always the best thing , unless there is a very good designed reputation system , things could go wrong. As far as I know , lending websites have a system to ask users for Residence,ID,passport etc... so you should be able to take actions against them unless there is something that prevents you from doing it. (from the ToS or something)
P2P can be harsh, like here, you need REALLY GOOD reputation system close to perfect one to this have any chance to succeed
the only way it would work is that the lending site itself took responsibility, and chased after scammers
since you hand over bitcoin to the lending site. you are not investing bitcoins on the scammer.. you are investing an SQL balance within the site with the scammer.
it is the lending site that "owns" the coins it receives and "gives" the coins to the scammer
it is the lending site that "owns" the documents and ID it is handed by the scammer.
it is the lending site that "owns" the coins it receives back (not often) and "gives" the coins to the user when they ask to turn their onsite credit into real bitcoin
the user does not get to see the passport or other documents of the scammer, so the users should not be taking the responsibility of loss. the lending site should
when a lending site just works as a chat room and then the users then privately tell each other their passport details and proof of residence. then the lending site can absolve itself of responsibility.
but when the lending site takes a users money, does the vetting of the scammer, promotes the scammer as credible and hands the money to the scammer
then the lending site should be involved with chasing the scammer. especially if there is no way for the first user to know the scammers life story.
but we know lending sites wont do this. so its best to just stay away from lending sites.