Well, the turf would be best if you never allowed anyone to play on it, but sooner or later most developers want to give it a try ...
Really, the question is how much play you're going to get. A few hundred or even a few thousand rounds won't do much damage to the turf, if they aren't using carts. You just don't want high traffic too early, because the grass has yet to develop any cushion between turf and soil, and it will wear more easily under those conditions.
The other part is, if you allow players, are you going to have to change your maintenance practices for the grow-in to keep improving? If there are areas that need to be re-seeded or over-seeded, you've got to keep those wet for a while, and golfers complain when the sprinklers are running.