This year the St Gervais commune is again running the Mont Blanc Info scheme. All summer 2 "wardens " will be stationed at Nid d'Aigle and at the Tete Rousse. Their role is to inform, not to police, and they are both friendly guys who are happy to chat. They are also gathering information on numbers of climbers, success rates, problems, rescues, hut overcrowding, etc.
There is also an excellent website here with all the info you need on hut prices, opening times, contact details, etc.
This seems to be a pretty positive move by the commune. They have a serious issue with crowding on Mont Blanc - there are over 30 000 attempts every year!- which causes safety and environmental problems, and this seems like a very reasonable way to deal with it and plan for the future.
