
Many times, this clause means there will be a monetary refund once a certificate of neutering is able to be shown to the breeder, for proof the pup had been neutered.
Just to add, we had to rescue an older puppy I'd sold into what I thought was a good home. I later heard from the owner who phoned me, that the poor girl was being traumatised by a returning squadie who was kicking a football at her (as well as to their Boxer). I suggested we went and got her out of there - she agreed but there had been no contractual clause about lthis - just that we would take any puppy back for whatever reason, and at what ever age.