I gave the method a try (although witha few % loss) and lost on two matches, and the thirds would have gone the right way, something just got in the way and I lost track of time and didn't get to wager the money. Had my doubts at first, as you say you need some courage, with some bad luck you would end up with just stacking your money on the bookie you just tried to get out of.
Well, not sure if you are thinking about just a good way of transferring money out of a bookie or like me, had problems with rolleover.
I ended up with staking the required amount of bets left in one siting. I picked 8 matched and sat bets at odd/even and both team to score, total of 16 bets = 1600EUR on 10bet and now I'm just waiting for my confirmation that I have rolled over (hopefully they will accept). I ended up with around 6% loss, so if i get the bonus I will break even. As a plus I lost 6-700eur on 10bet in the process.
Edit: bonus confirmed
Thanks for the help guys