Recently I had a guest who stayed for 5 weeks. As you know, when you accept a long-term reservation, your payout is released on a monthly basis and Airbnb will schedule a recurring payment after the first month.
However, things start to go downhill when the recurring payment fails. Maybe the guest instructs a credit card issuer to decline the future payments or due to insufficient funds in their bank account. Either way, Airbnb sends you an email "Problem collecting payment for reservation [reservation code]" to let you know that the attempt to charge your guest for the amount due for the reservation was unsuccessful.
The email also states that "If your guest doesn't successfully submit payment or if they cancel the reservation before making the payment, Airbnb isn't liable for issuing your host payout. If you prefer to cancel the reservation, you can cancel without penalty at any time before the trip begins. If the reservation has started and you'd like to cancel, please send us a note."
We shouldn't receive this email before the reservation starts because the reservation can't be confirmed without a successful payment. Problem arises when the guest is already in your home. They could stay for free after the first month and we (hosts) can't do anything about it. Airbnb won't do anything about it. We will have to take the matters to a small court or the local police to remove the non-paying guest.
It seems to me that the only way to prevent this happening in the first place is to limit the max number of days at one month. If anyone wants to stay longer, we should ask them to make multiple bookings, so all the payments for the duration of their stay are secured at the time of booking and your cancellation policy will apply if they cancel/change the trip length.
I eventually received the money. Not sure if the guest fixed the payment issue or the email was sent to me by error. Airbnb support has been shifty and doesn't answer all of my questions.