We were fortunate with a 3 gal glass carboy once, I noticed a little puddle of wine on the table, curiosity made me look closer as I had not been working in the area for a while, and I could see the crack forming at the bottom of the carboy. Freaking out, I grabbed a clean bucket, my wife held the bucket while I gently and carefully slid it to the edge of the table and it held together long enough to put it in the bucket. We Racked it and when lifting the carboy out of the bucket the bottom fell out. I guess when Jagg said explode I thought he meant really explode, but the bottom falling out is just as exciting. Pumping between carboys would keep that from happening as long as you dont move the carboy around first. WVMJ