It just a simply "guarantee" that they will cover guest caused damage.

If so... do you make the guest take rental insurance or something? 

If you know the person really well, know that they know real estate, that is worth more than gold.

Commingling of funds could have legal consequences for your entity's limited liability status. 

Some GC's are only as good as their sub's and other's are better than their sub's and are worth their weight in gold - it all depends.I've don't most of my projects with sub's for many years and have learned to recognize many things that may need more attention, etc.

But I do have it listed on MLS for LTR, I’d much rather a short term guest though - since I’m so close to college and university hospital, I’d hope for students or traveling medical professionals. 

@Jerrell Sweeting   I know in NJ this was the difference between eviction(tenant) and ejection (just a " guest, no money agreement) of a person.   

I've used Airbnb and they have reimbursed me for repairs when a guest does damages, but they take a lot of time and the reimbursement is not always what I expected.

They will handle all aspects of renting out your second home.Long-Term Rentals (LTR): The management firm can find long-term tenants for your property, screen potential renters, handle lease agreements, and manage any issues that arise during the tenancy.Seasonal or Short-Term Rentals: If you prefer to rent out your property on a seasonal or short-term basis, the management firm can handle marketing, bookings, check-ins, check-outs, and cleaning between guests.

This is gold & explains it!