That's a good question.
I have no idea, but I bet it has to do with how CNS and the staff evaluate people.
Reminds me of the story Bob Baumhower tells of how he ended up at Alabama. Only D1 offer he had was to Vandy. Bama staff was looking at an O Lineman on tape that they were recruiting. Bear ask his staff, "why the hell aren't we recruiting the D Lineman that was eating his lunch the entire game"? Bob said there were several Alabama coaches waiting for him at the airport when he got home from an "official" visit to Vandy...........the rest, they say, is history.