This isnt a comnplete scam - merely a technique to help you use other scams or get a target player to hepefully drop some of their defenses and thus become more suseptible to a scam.
Basically - lots of players have not left home, many have brothers or sisters that share their accounts, or are aware of the fact they play WOW.
Pretend to be someones little brother, that has just got on WOW onto their big brothers account ansd is having some fun. You might try the backspace scam for example, asking the other player if 2000g is a good price to pay for a krol Blade then saying they need to trade quickly becasue you think you can hear your big brother coming back in the house etc etc.
The psychology behind it is well known - peiople lower their defenses and suspicions once they feel superior to someone else - this makes them vulnerable to a smart scammer - especialy if you get their greed gene working over time.