So I'm working on a web based game, and need to deal with the age old issue of duplicate account detection.
Players often create multiple accounts to farm money/items etc to their main account, or to stash items etc.
In the games I've typically played the main way this is done is by preventing multiple account to be used on the same IP within a certain window of days. If it happens repeatedly the newest account is banned.
The problem here in my mind is that the determined players just use a proxy, and it also prevents family members from both playing the game in the same home.
My idea, is to handle this another way. To keep a running tally of the 'networth' of items, money, etc that each account has given to another such as in trades, gifts, lost duels, etc as well as track the # of such interactions. Then if I detect accounts which have a large # of trades between the same two account with a growing networth traded from one account to the other (usually from the feeder account the the main one) I can then reasonably assume that these are suspected of being dupe accounts. If the amounts or small, and/or the frequency is small then it can be allowed.
Am I missing any glaring holes in this approach? I realize that small fish may stay under the radar, but these people would likely use a proxy anyway. And it will not prevent family members who make occasional trades between eachother.