Something that's been bothering me as I've watched this thread develop, ever since I first learned (or relearned, I think I knew it once) that TOGA is inhibited by the squat switches..
If TOGA is commanded in this situation, is there any aural or visual warning?
One of the basic precepts of user interface design is that if an action is commanded and it can't happen, the user should be made aware.
I know that the cockpit is a busy place during a go-around, and that pilots are fully committed in managing the situation, but it's not such an abnormal occurance that an additional klaxon or bell would be sensory overload, and surely you'd rather know in time to push the throttles forward? Accidental commanding of TOGA in a non-safety critical situation - in the cruise or taxying to the gate - seems vanishingly unlikely to occur and if it does and there's an alert, no harm done. Presumably that's why there's a suppression circuit in there anyway.
(It's also not a complex addition: I know this is the thing that every armchair expert says, but in this case if there's anything less complicated than checking if the TOGA system is suppressed when the button's pushed, I'm hard pushed to guess what it might be)