The only due diligence possible is an AirBnB-provided, essentially anonymous, IM conversation. Anyone who attempts to use the AirBnB service who isn't running a legitimate short-term rental property (with all the associated insurance and safeguards) is playing russian roulette with their property and possessions. And if they're home during the rental they're potentially risking life and limb.

This is a failure of the business model. If they are unwilling to get into the business of creating a safe, vetted community for short-term rentals, they need to disallow personal rental properties and stick with full-time rental companies.