That can be an acceptable risk actually and it does quite often. There are two conceptually different phases in SDLC: verification that proves implementation is working according to spec and validation that proves that spec matches business expectations. Automated tests work on first phase, minimizing the risk that when reaching the next phase we will be validating the code that wasn’t implemented according to spec. If that risk is big enough, accepting the refactoring costs after validation may make a lot of sense.