I can speak about d3. Since there is no athletic money, there is no NLI to sign. A D3 commitment is equivilent to a verbal commitment. The coach does not know the player will attend until he shows up in the fall.
When you block a person, they can no longer invite you to a private message or post to your profile wall. Replies and comments they make will be collapsed/hidden by default. Finally, you'll never receive email notifications about content they create or likes they designate for your content.
Note: if you proceed, you will no longer be following .