The question isn't.. "why are they scamming out?" its more like.. "why are members so gullible in trusting these retarded new users?"
If I didn't think to look at there join date, and examine there grammar and behavior ect, I would be tempted to trust these fuck heads.
Here are some rules you should follow:
Stop going first to new users who joined less than 3 months ago ect.. There not trustworthy and won't be for a long ass time. Until they have been hear for over a year or more they are considered a flight risk.
Stop accepting paypal from new members.. If there trying to be legit and are being serious about wanting your item.. they WILL order btc or find a way to get bitcoin.
Use a middleman.. but choose wisely. There are a lot of fuckhead middlemen out there.
If it seems to good to be true.. be cautious, but stay open minded. There are a lot of legit fuck heads out there who are legit and you could possibly lose out on that amazing deal. If they refuse to go first or use a middleman then its best to move on and consider it to good to of been true.
Do your research.. ask some friends about that user if they know anything about them.. do a bit of investigation and find out who you are dealing with and why they want your item ect..