I think it would mean that it would be more likely for a court to scrutinize the terms of the contract with an eye toward whether they were reasonable and fair, rather than simply enforcing it as written.

(ETA:) This might not help very much, because in places where noncompetes are standard, a court would be sticking its neck out a little to rule that one is unreasonable. But maybe it would help a little, if one couldn't get the provision struck from the contract altogether, and had no reasonable alternative to accepting the job. (Again: IANAL, and I'm just speculating -- no one should take this as legal advice!)