As I've mentioned elsewhere, I use a 1/2bbl keg to ferment in. A few ferments ago a batch I'd pitched the night before started with a small steady bubble. By the next day it had stopped completely. No problem, I new this meant little.
Well when I went to push the beer over to a corny, I got a face full of beer from a highly pressurized fermenter! After a quick WTF moment it dawned on me,... I'd forgot to remove the gas check valve from the coupler before attaching the blow off to it.
I found out by accident that you can in fact ferment and carb at the same time!
Beer turned out fine, but I've went back to the multi step method to say the least.
May check into this type of fermenting/carbing at a later date. It won't be by choice tho.