I do all my betting via betfair so haven't run into this issue.

It feels wrong that they can do this, but at the same time there probably wouldn't be as many bookmakers if they didn't do this. Letting them ban winning punters gives more options to those who lose.

I can't understand how being a bookie could be that hard. Wouldn't you just put all your odds less then betfair and automatically lay them all off at the corresponding prices. Your commission would be reduced due to the discount and it would be semi-easy cash as its all automated. I have rarely seen a bookie with prices higher then betfair in my travels.