I've had the reverse situation happen, where IB received a bad tick that triggered one of my stops. If the stop order lived on Globex and not at IB, it would be less likely that my stop order would have been hit (and if it did get hit, many other orders would be executed as well). Then there was the time a few months ago that IB's connection to Globex went down, and my two stop orders did not get filled (both resulting in a nice profit on a nice range day, with one of buy stops just a few ticks from the low-of-day). But overall IB has been a great execution platform for trading Globex. If stops could live on Globex instead I believe it will be much more reliable. No matter how much redundancy and fault tolerant systems IB puts in, it is always more reliable to have your orders live on the exchange than one hop down.