I bent a steel bicycle similarly once... not shipping it, but rather I rode off of a very high curb at a pretty high speed.... not intentionally, the pavement was new, the curb was white and it was noon, which all added up to a very pretty optical illusion that it was a 2 lane bike path with a white divider in the middle rather than a 4 inch drop off.... I went off of it a probably +20, I landed it without falling fortunately, but the rear wheel taco'd about a mile later and after wearing all the teeth off my rear derailleur's jockey wheel a week or so later I found out that I'd bent the seat stay too. The guy at the shop bent it back and all was well. I had that bike for several more years without incident and without it rebending.