Wow that sounds like a +1.0895 expectancy. Sounds like the bookies have really fucked up.
Yeah it's hard to be a small bookie, there are probably many arbitrage opportunities if you bet at small bookies like at horse races and things like that. If they don't react fast and match their odds against others then arbitrage opportunity arises.
But online betting is different, here the market is more liquid, and the possibility of arbitrage, of any kind, is lowered if the market is liquid.
One time the odds were really inflated. I put 50 down they adjusted it and I cashed out offered me 300, I took it. Quickest money ever.