Hueys and Cobras (AH-1G's through AH-1S's) are limited on the low side to +0.5g's because of main rotor flapping as well as the dreaded so-called "dihedral roll". If you push over too hard and get negative g's you get an un-commanded right roll due to tail rotor thrust. If one adds left cyclic to correct the right roll you enter mast bumping which is usually fatal. The correct procedure is aft cyclic, keep it in trim, and ride/fly it out. Nothing to do with structure.
I was in it once in RVN and I paid attention after that.