Some interesting answers here...
Stu,
Only having caught a handful of GT's myself I don't have a clue. But what I personally noticed is my landed fish where hooked on the bite (at least I think so).
The fish that didn't hook up (and for all money you thought you where solid) would bite the lure and just hang on, I had a few take the lure pretty deep where I had to wait for 5-8 seconds for the popper to surface, striking would have achieved nothing IMO, as Brandon stated... When GT bite down, that lure won't move. As I was testing my own lures I was inspecting the bite marks/position etc... pretty closely, what I noticed is the GT's didn't "chew" on the lure, they just smash and grab...and lock down. If a hook hasn't found home at this point I don't think it will.
I don't have a clue is what I summarised and just kept on casting