My parents had a tenant that didn't pay, created damages and had to evict, the insurance company made them jump thru hoops to try claim in the end to only deny them.

I've heard of them denying loans on homes with gravle driveways.  

Liability insurance is a great help, but you never know if the company that writes the policy will try and deny any claim due to negligence on your part.

My previous tenants are denying the damages and filed against me in court.  

If you're denied, ask why and how to improve your application.

I have heard that since the, VRBO for example, insurance policy is actually purchased by the tenant they are really quick to deny claims.

They may also apply an affordability test and could deny the increase.  

If you are denied, which you should not be, read your denial letter carefully and find out exactly why you were denied.

I know a couple have denied it and made me put it in my personal name and even restricting the deed for 60 days.

Looking at probably $20k-$30k in total expense here.Filed a claim with our insurance (commercial policy), and initially, the adjuster said we aren't covered for sewer back up, so she was gonna deny the claim.