Dropped $60 on a bike stand clamp that marred my buddy's carbon frame

So about 4 months back I grabbed this clamp-on repair stand off Marketplace for $60 because my old one tipped over and I figured it was an upgrade. First job on it was my buddy Dev's carbon road bike, and I cranked the jaws down like I always do on steel and aluminum. Heard a little crunch, didn't think much of it, finished the tune-up and sent him on his way. Two days later he texts me a photo of a spider crack right where the clamp sat, and the frame guy in Kalamazoo quoted him $400 for a repair. I felt sick, and I paid for it because it was my fault. Turned out the clamp had metal teeth under the rubber pads that were worn flat, so it was basically gripping carbon with bare metal. Now I only use padded jaws and I barely snug them, plus I clamp the seatpost whenever I can. Anyone else get burned by a cheap stand, or am I the only one who learned this the expensive way?