Unlike the 305 or 310xt, the Global Trainer is supposed to be especially designed and marketed as a triathlon GPS watch – it carries the IM name. The waterproofing suggests it is intended to be used during all phases of the race. GPS signals will be lost in the swim. A tri specific watch should be designed with the expectation that during a race the user will swim with the watch on but want the GPS signal to acquire for the bike & run portions. It seems to me it would be a better tri watch if it allowed users to disable the nag, just like we can disable GPS.