if we had the room I would make this a sticky since I seem to post it a few times a year. With NCAA prospects you have to remember they fall into 2 categories. They either qualify for the loophole or they don't.
In order to qualify for the loophole said draft pick MUST not go directly to the NCAA after being drafted. If he's drafted and the next season he plays somewhere other then the NCAA, then he qualifies for the loophole. That means that if he wishes, after his Junior year he can inform the team that he is going to opt out and become a UFA on July 1st that follows the end of his junior year.
If said draft pick gets drafted in June and plays in the NCAA in the fall, or was drafted out of the NCAA then they do NOT qualify for the loophole and then they must be signed by August 15th following the end of their Senior year. They can chose not to sign and become a UFA after August 15th.
ANY prospect can refuse to sign with an NHL team. If they do it depends on their age if they are to re-enter the draft or not. Since most NCAAers will be over 20 by the time they can refuse to sign they are too old to re-enter the draft.
So for the Habs, Poehling, Primeau, Harris, Gorniak, none of them qualify for the loophole. Hawkey did qualify for the loophole last year but he didn't go that route.