Just adding my twopenneth...
Being fortunate enough to live by the sea I am not interested in the resort type holidays and trips are chosen, as for Charleyhorse, by reference to the destination and whether the trip ticks all my personal boxes as to the places I want to go to and see.
I have used another company from time to time who have a few days ago sent me their brochure for their brand new solo holiday arm so I suspect this new policy is perhaps down to sensitivity with giving out too much information to competitors.
Whilst absolute numbers are not, to me, a deal breaker I sympathise with those who like this detail.
However, what we also seem to have lost is information on the departure dates pages about tours filling up. I have looked at several at random and the only information that now seems to be there is "Available" or "Sold out". There has in the past been additional information as a tour fills up alerting people to the fact that there are only 3/2/1 or whatever places left. I can not see that this is in any way competitor sensitive and it is a very good marker if you are looking at long term planning, have annual leave to book, are saving up etc etc in helping decide if you need to book now as without any warning that the tour is filling up you can easily find you have missed out.