Just thought, for future applicants, it might be worth sharing our experience of Camden School for Girls waiting list. Aware that this is just one data point, but it might be useful for someone in years to come.
We don't live near enough to CsfG for any realistic chance of a local place so let our daughter apply for music place. She was keen on all-girls, and quite musical having done Gr4 in a non-orchestral instrument. She got through the 1st round aptitude test (top 50 out of not sure but over 100 we assume) and then did the audition. She auditioned with her instrument and voice. They offer 3 direct from the aptitude test and then 5 from the next 50 who have taken the audition (ability stream).
Afterwards the school told us she was 41st and 15th on the aptitude/ability stream waitlists respectively. We were also were told which band she was in from the separate banding test.
On Friday (4 days after allocations came out), Camden told us she was 17th and 6th on aptitude/ability stream waitlists respectively. (Also 34th on banding). Obviously it will vary from year to year, and no way of knowing which numbers on the list have "dropped" out, but essentially half of the music waitlists above us either got allocated a more preferred school, or rejected the offer in the first few days after allocation.