Nah... pretty sure in that scenario, the SHA-256 dude would get sweet F.A. You need hashpower to discover the blocks, regardless of the algo. The 1PH Scrypt network would find everything, except in the most bizarrely lucky of situations.
Except he was wrong. Each algo would have it's own difficulty thus if you were the only one on SHA256 you would get the same amount of coins as the total of the Scrypt miners.
Its really quite simple the way the Dev explained it "Imagine that DigiByte is 5 different coins in one. Only 1/5th of all DigiBytes can ever be mined by the SHA algo. So if you have a SHA ASIC you still are competing for 100% of SHA-256 DigiByte coins."
Yeah, on further contemplation... I realised my mistake...
All good. Just want everyone to understand how it works!
What should happen after things shake out is each of the algos will be about evenly mined so there is not a huge advantage to one or another as far as rewards/difficulty goes.