Yes, the guest can lie and get a refund. This is a business for Airbnb and they have a surplus of unrented rooms every night. Their business needs more renters so they will put importance on the guest. If an averge host gets upset and leaves the site, Airbnb will make the same amount of money as guests will just find another place to stay. If a guest leaves the site, it will be a lose of profits for Airbnb.
It is not personal to the venue, it is business. It is not about being right or wrong, it is about their botton line.
They will give the benefit of the doubt to the guest because at this time, they put more value in the renter.