My last 6 or 7 batches have all started fermenting vigorously in under 2 hours after pitching. All of them have had significant blowoff. I usually just let it go and make a mess (the basement floor is vinyl tile and pretty easy to mop up) and then clean things up and replace the airlock 24 hours or so later when things subside.
But then about one month ago I had an epic blowoff event that made me change my thinking. I did my usual routine of pitching the yeast from the starter, oxygenating, etc. and then cleaned up the brewery area and went to bed. The next morning I woke up and went down to check on things and I noticed that I had a pretty big eruption and there was a LOT of beer on the floor. Instead of the airlock being near the carboy, it was nowhere to be found. There were tiny bits of trub scattered on EVERYTHING in the room. I mean EVERYTHING. The door to that room was open during the night and there were even bits of trub on the door to the room across the hallway. I'm guessing the stopper was in the carboy very tightly an a lot of pressure built up before it finally let go.
At any rate, I went out and got some large diameter blowoff tubing and used it on my last 2 batches. It's a ***** to clean the inside of the tubing but after that big "explosion" and the resulting mess I think it's worth it. Of course, I could also stop oxygenating, making starters, using yeast nutrient, etc. and I'd probably not have the rapid fermentations anymore, but I think despite the blowoff issues all those things make better beer so I'm inclined to keep doing what I'm doing.