Tips to stop scamming,
1.Make sure your logged in to your email on a nearby computer.
2.Change your password to something u never use for anything else ( note it down u might forget 5 mins later )
3. Go in to Account management, billing information, make sure to CLEAR everything, check it 3 times.
4. Delete all sent and recieved messages just incase any data about yourself or friend is in there.
5. Dont do it with anyone u dont know even people u play with all the time on PSN.
6. Make an account on you PS3, add your Main account to that one and ull be able to see when the person logs off or on, they wont know your watching they will just think its a friend.
7. As soon as they are done Log back in and change your password back as fast as possible.
8. If they stole it your already logged in to your email. so you'll recieve an email if he changed your pass or made a purchase, be very careful keep a phone with sony's number near by, even go as far as to have your bank number (make sure its the one for stolen card} and tell them 2 freeze it if your Credit card details are in it.
9. Always be prepared to act fast and do not let ur attention be distracted at all, only do it when u have ur full 100% attention.
And one of the most important ones:
1. Look at the Trustworthy and Untrustworty List