At the Stanford camp, I think almost every 22 and 23 committ was there - which is impressive considering they seemed to mostly come from the East Coast. Level of play was high and the campus is - WOW - this time of year.
Why would 22 and 23 commits be there? Do you mean players that have already committed? Are they hoping for a potential upgrade to another school?
In general, a schools committed players usually attend the schools camps.