The terms of the policy dictate what coverage is provided.

Seriously, my opinion is it's ridiculous, but on the other hand, so are umbrella coverage/liability insurance premiums and our reputation is all we have in the end.

Also, this may effect insurance coverage claims.Check out this damage from a rage AirBnb_rage

I would love to buy A class, but based on my experience financing these is really tough as these don't cash flow well, the banks usually wants a certain debt service coverage ratio and these being pricey really never works out.

Here is why: 1.They have let our property insurance coverage under their master insurance policy lapse for 6 months due to non-payment while still deducting from our rents to pay for the insurance premiums, and exposed our properties and tenants to tremendous risks and liabilities.

Premiums are going to vary based on things like policy coverage, deductible amount, claims history, etc.

Purchase an Umbrella Insurance PolicyUmbrella Insurance Policies are used as additional coverage after landlord liability insurance is reached.It’s also used for claims from a tenant, guest, or adverse possessors on vacant property injured on the property.

Associations were delaying the processing of claims that they were responsible for and hoping the Unit owner would pay it or put it in to their coverage. 

I'm specifically wondering what kind of insurance house flippers maintain.I have builders risk on all the properties that has liability coverage as well, but am interested in getting an additional umbrella liability policy as well to have additional coverage.Unfortunately, I'm getting quoted super high rates on it- I guess due to the perceived liability from flipping 20 houses a year.What kind of insurance do other house flippers here have?  

They will work with you and they have great insurance prices with good coverage.