Nope, doesn't work
It still just plays the vsay & displays "Fire in the hole!".
I've tested the script in vanilla, nitmod, jaymod & etpub - same results everytime.
What I don't get is why this line works:
set grenadethDefault "say_team ^7Timing Grenade! ;set grenadethON vstr nic"
and this one doesn't:
set gtOFF "-attack;vstr grenadethOFF;vsay_team FireInTheHole ^7Throwing Grenade!;bind mouse1 +attack"
I've seen people rename the displaytext of a vsay, that can't be the problem.