I just had one of these this week. A guest (also a host) booking from Austria, with good reviews.
He requested to book, and his introduction to me was to ask if I offer free parking. Which did seem to be a strange thing to open with as both a host and a guest coming in from Europe, since I mention this in my listing. I responded, and we chatted about wifi. He seemed ok with everything, and I accepted the request . It went into a status of "awaiting payment".
Since it was an international reservation (I thought, from his listed location), I gave him the benefit of the doubt until the next day, as I have seen that happen with international credit cards.
Next morning, I reached out to let him know the status was still "awaiting payment", and almost immediately the status changed to "request withdrawn". I then received an email from Airbnb saying they cancelled the request due to payment not going through.
It all seems a bit weird to me. The guest could have withdrawn the request or cancelled without penalty at any time, if he was unhappy with any of the items we discussed, since I have a moderate policy. I did wonder if a guest can deliberately withhold payment if they don't want to cancel, knowing that Airbnb will process the cancellation due to nonpayment.