Does the guarantee hold anything in sports anymore

Just watched the cleveland Orlando game after Mo williams "guaranteed" a victory. Orlando won and nothing seemed different in what Williams did. How overblown is a guaranteed statement in sports now? does it really mean anything? Shouldn't we be under the impression that an athlete goes into a game thinking they will win for sure and give their top performance under any circumstance? I can understand what it sort of meant went Joe Namath did it in super bowl III because no one gave them a chance, and Namath showing confidence was kind of forbidden at the time. But with guarantees in seemingly every other playoff series now, they seem really stupid because athletes just say them for virtually no purpose. Unless you plan on pulling a Messier in the 94 playoffs and score the game tieing and game winning goals (i believe), after guaranteeing a victory, don't bother. All your doing it needlessly drawing attention to yourself that does not add anything to what you or your team does.