1) Airbnb has a crazy insurance policy [1]
2) Both the host & guest get reviewed. A single bad review can impede your ability to rent on either side.
This is purely based on my experience, but it seems like guests really don't misbehave.
Maybe there is the occasional party or guest who trashes the place. Good hosts tend to hire cleaning services to deal with messes. Generally, guest are tired from traveling and doing activities and are low impact.