If someone cares...
May be the most easy mode to detect. As when the round start you're already full of power. (In training mode, the power grows at the beginning).
So, to detect demo mode (to set AI->ON), go to the pre-intro state of your char (the [state 190], may be in mugen\data\common1.cns, and copy/paste it in your char.cns file. Then add only these lines :
[State 190, 4] ; AI in demo mode
type = VarSet
trigger1 = Power > 2990 ; This number has to be close to char's power max value
trigger1 = Time = 0
value = 1 ; <- The var value is set to 1
v = 0 ; <- This is var(0)
May be you can test :
trigger1 = Power = 3000This would work but as I don't know how the engine fill the power bar at this time... I prefered to put the version above.
As far as I remember it's compatible with Winane's Activation code, where Var(0)=1 means AI is activated.
AFAIK, Winane didn't add a special part for that demo mode.
The good point here, is that we can be 100% sure* that AI is going to be activated even before the start of the show.
* : Except may be if you add Winane's Training detection mode bonus :
; ONLY if desired:or some same stuffs...
[State -2, Start Full]