The problem is it won't get as far as trial, if the old company gets wind of it early enough (and they often do). The old company will reach out to the new company and politely inform them they believe they have grounds for a noncompete suit. The new company will either indemnify the worker, or (far more often) drop them as not worth the hassle, and take their #2 choice.
The legislation needs to change. The situation as it stands is ripe for barratry and bullying.