I've only ever noticed the Glee's ABS kick in when I've braked on uneven road surfaces (the tyre skips), going over manhole covers when wet and twice during emergency stops. The back brake is more sensitive (or my boots are less sensitive).
When we were in Scotland my brother could have done with ABS when he locked his cruiser's rear wheel (poor braking technique) and ended up going off road... the Glee's ABS kicked in then too but I didn't go off road.
