Welcome to the Community. If you care to, you can look for and read all of the questions about screening which comes up regularly, here. A number of Members have described what they do (including myself). You can find earlier postings on this (and every) subject. To find topical subjects here, you can scroll to the top of this Community page...and just under the little birdhouse logo, there is a field for *Search*. Type in the word, 'screening', for example. All the earlier posts with screening methods will appear. My comfort level with individuals inquiring is very much dependent upon what they say in their initial inquiry...and then how they respond to me (especially to any questions that I may ask them).
But, before I respond to that initial inquiry, briefly, this is what I do.
I do a combination of an initial Google search (for a minute) on any of the data that was provided in the initial inquiry (name, email, tel #)....and I use an online resource I subscribe to (PeopleSmart -- which I find helpful...it locates people, provides phone, address, social media account, etc....but I do not do "background checks" into criminal history, etc.. ) The inquiries I get via VRBO can often be quite negligent...sometimes only a first name...no tel #..emails that lead nowhere so I started using PeopleSmart to see if it helped...and I renewed it for another year; it helped me to identify someone who I was suspicious of (a local resident who was a known problem) that was trying for some time for access to my place. I stuck with that service as it helped me a couple of other times with potential issues...I do use it a lot but not with those inquirers that are forthcoming, right away. I only do short-term rentals and people travel from afar to reach me....purely for vacations...although sometimes I am approached for housing under various guises and scenarios I am not prepared to provide for. My inquiries come through not only from listing sites (like VRBO, others) but also via my own website....all vary in "inquiry quality" in terms of how much information people divulge when inquiring.
Facebook and LinkedIn account also helps when I find those online through the initial, first, screening. I do this screening...regardless of who is inquiring...regardless of the duration of their proposed stay...but I do not want monthly contracts. I do not spend more than 5 minutes on that initial screening. Google Earth, once an address is known, also reveals a lot about prospects. But, I do my best to remain open-minded about people -- as long as they answer my essential questions (I send them along with the rental agreement...if I am interested in them as potential guests...but... if initial screening leaves me still uncertain, I will send only my essential questions first). I try to remain open to processing them for a stay until I have a reason to stop considering them. Of course, if a Facebook page or other social media presence reveals questionable behavior, I refrain from offering my place. A couple of times I found videos on YouTube that disqualified those people from getting my keys.
I've *never* had an issue with anyone refusing to answer any questions or returning a contract, fully. Not yet, anyway ...(I knock on wood as I write this.).
I've also never heard of or seen anywhere on HA or anywhere else online that has a place for homeowners to leave feedback on guests. Please share the link.
Here's kind of an off the wall idea that I've heard of others doing... ask the guest if wouldn't mind providing who else they have rented from and then contact the owner or property manager for their feedback. Their feedback is worth more then any background check site or Google search.