This actually has some real potential if true, Blaziken gets mirror move and commonly runs protect for speed boost, luring out an attack to fulfill mirror move's condition without arousing suspicion beyond not mega-ing.
Assuming the boost is before the Z-move comes out and so applies to it, you can then so some crazy damage in return while ending up with a +2/2 blaziken to sweep with, the the opponent switches or throws a special/status move into protect, you can still BP away and give something +1 speed.
You can outspeed and OHKO things like Pdon (copy e-quake or precipice blades) and Mega ray (copy anything not EQ and waterfall, you even tank a +0 e-speed uninvested and OHKO back with that if it tries to outpriority you) this way thanks to speed boost, and can then pass +2/2 (or 2/3 if you protect again) to some scary attacker if blaziken isn't enough for you to kill things with. You can also do this if they switch out of mirror move to stop it.
Probably not consistent, but turns games around in an instant if it works.
