Arbitrage

Do many of you back and lay between exchanges (e.g. between Betfair and BetDAQ) or between an exchange and a bookie, to get better gaps between back and lay prices?

I was watching the prices of some football matches and horse races on Betfair and comparing the odds to a couple of bookie sites and also BetDAQ. There were a number of differences between them, which means ways to make a profit. I might be being hopelessly naive, but I think there are still opportunities here. As time goes on, they will get less and less as people set up bots to automatically look for these and perform the trades.

Just wondered if many people are looking in this area.