Put up a brew before leaving for holidays. It's one and the same beer (Saison with Fermentis BE-134) in 2 carboys, didn't have enough stuff for a regular bucket, but too much for one carboy. Before I left, the krausen was already pushing through the airlocks as you can see in the pic attached. I knew it was risky not installing a blowoff tube... "calculated risk but man, am I bad at math" kind of thing. Returning from 10 days away, the locks were completely gunked up with dried malty stuff, yummy. I took out the stops and just covered with aluminium foil, left for a total of 1 month, racked the content of the 2 carboys together and bottled from there. The brew smelled nice, but seemed to have an overtone of vinegar/cider or something - faint enough for the risk to be worth it, I thought. We shall see in a month or so if it's drinkable. I think one of the carboys smelled more cidery than the other, but I didn't compare properly.