FriarFred, to clarify your understanding, yes the NLI is binding on both parties. However, the athlete's scholarship will only count against the coach's 11.7 limit if he enrolls and attends classes at the college.
If the coach convinces the athlete during the summer before he enrolls that he isn't going to get playing time (for whatever reason) and would be better off going elsewhere, that coach probably feels like "no harm, no foul" as far as he is concerned. Obviously the athlete and family won't feel the same way!!