Same here. I am an active host, and would find it very useful if I could contact guests that have been added to the booking. E.g. the girl who booked today, just messaged me to say she got ill, and is not coming. But her other four friends, yes, are still coming. She thus said that a second person in the booking will be the point of contact. I can see his picture and profile, but I cannot message him. I have a smart lock system (self check-in), so I need all communication to be secure and verified via the AirBnB chat. Whatsapp or SMS is NOT an option in this scenario. Would hereby like to raise a feature request to the AirBnB technical team:
Please activate chat between host and all members in the booking. Tnx