I think they would identify the price range where most of the traders stops are placed and then push the price to that level to trigger the stops. I'm not sure if a hidden stop will help us as the ea will close the trade when this faulty price data comes through anyway. The more brokers that do this the more the real market price will move to that level as well so what can you do?
The only thing I can suggest is that in very volatile periods the ea must not move the stop too quickly. And only move the stop after checking that the 1 min price data is not faulty by looking at the size of the move over the last few minutes. Yesturday Alpari sent me live 1m data on 02/04/2009 at 13.45 - 13.46 that totalled a 90 pip move in 2 minuites crazy! of course my ea moved the trailing stop and was stopped out when the prices returned to normal 3 mins later

. I will have to make some changes for next time.