Question about waitlists

so for waitlists when it’s an early morning class they text within the 10 hour window saying type 1 to get off waitlist, but whenever I have a class in the afternoon I never get a text.

I always thought people just didn’t late cancel but I am on a waitlist for a 5:30 class today and I just went from being #5 on the waitlist to #4 but no text…is the policy different for afternoon vs morning classes?