Hi! I was looking around for a spot in Poole area for June and sent a host a message to ask about proximity to an event I'm attending. We'll have kiddos with us so walking would be great to help wear them out a bit :) However, AirBNB tried to take the payment even though I hadn't made a reservation request, I simply asked a question of the host. I've been a guest traveller a few times and this never happened before that I can remember. I got a prompt that my payment method failed, and then it said that when I correct it, the reservation will be confirmed immediately (but I didn't make a reservation request....so in a panic I simply didn't update my payment info!).
Are you sure you were on the official AirBNB site? There are many scam sites that look exactly like Airbnb, and this behavior sounds like something they would try to do.
Absolutely sure it was 'the real deal' as I went right from my own listing, to browsing the spot where I stayed in Poole last time, to the search bar to look for another place (as they were booked). Maybe I clicked the button instead of contact host? I guess it's not impossible just thought it not very likely I'd mistake an enquiry for a booking myself hehe :)