arbitrage betting

A few years back i nearly bought into a program from the gold coast, that allowed you to place arbitrage bets.
You had to have about 10 different betting accounts and then it showed you bets to make through 2 different online betting sites. They only used sited that you confirmed your bet and price so you would open 2 windows and get the confirmations before proceeding.

I got to watch it live and yes it seemed fool proof with claims of doubling your money easily in 6 months or so.

Ultimately i walked away as it just seemed to good to be true. cant remember what it was called but just wondering if anybody used it and came unstuck.

The only problem i could see would be that you need to keep pulling money out of your winning account and stick it back in the losing account and the fee's would chew up on your profits.

Also while the program cost 10K or so you didnt own it, it just gave you access to there site, if they ever went broke you had nothing.

And the age old thing if there program really worked, why sell it? Why not just use it with out any over heads???