CAS, I have used H.F. blades exclusively ever since they were first mentioned here. I have had not one problem with them. I do not think they will bend and if anything, cutting with a pin under your fabric, very definitely will put a knick in them. We need to be as careful with our $1. blades as we do out $5. blades. I have 3 different rotary cutters and they work very well in all of them. I don't understand what you mean by "or something." I bet you could cut your fingers very easily if you were not careful....or something!
Harbor Freight has a very generous return/ refund policy. If you get them via email you may return to any store for replacement or refund.....but you will need your receipt.