It feels like it's been more successful than they'd imagine and it does sound like it's got a bit out of control hence their max limit of 200. I do agree that that's too many people at once, but I'd hope that as I mentioned that people gain confidence to go out on their own. I bet there are people on the walks who never imagined in a million years that there would be another 200 people there and who'd prefer being alone or on smaller groups.I applaud the group but 200 on a walk is insane especially if they only have a couple of knowledgeable guides. 20 max would be sensible and less if possible.
However I entirely endorse Yu Shan's comment about being descended on by that amount of people at once, fastest way to destroy any hope of welcome and integration. Goodness knows enough people complain on here about crowds of twitchers who mostly know what they are doing!
As an aside, they were asked what their top two suggestions were for people getting into birding and it made me think of the thing I always suggest for newbies: don't be overwhelmed by all the birds in the bird book. Become more familiar with birds you see around you and then gradually build up the number of bird species you see.
I can remember being just out of primary school and looking at my first bird book and thinking I could pop out for a walk in some nearby farmland and I'd see a golden oriole - it's about managing expectations and easing into the hobby.