Lay the draw - Sports Betting Strategy of Marian

I think this is a well-known strategy, but it works, so here it goes:

I choose a match that, according to stats i check with a software, will not finish 0-0 .
Of course, Betfair must operate an "in-play" market on the match.
Before the match starts (or sometimes i wait a few minutes), I lay the draw at the best price I can get.
I stay glued to my PC during the match and as soon as the first goal is scored and the in-play market comes back from being suspended, i back the draw (at higher odds than you laid it) with a stake calculated to give you a surewin. i.e. to recover the liability from the Lay bet and still show a profit if the match does finish as a draw. (i use an excel spreadsheet that calculates how much do i have to bet to win anyway).
Of course, if I think the match won't be a draw, I can wait and win more when the odds go higher, or i just don't back the draw if a team has 2 or more goals difference.

One thing that can be done to be sure that you will win, is back the 0-0, so if the game is scoreless and the draw odds don't go higher, you still win or at least you don't lose too much.