We never buy down nor pay for any supplemental insurance. We always take the time to understand the full risk we assume when we buy a house, car or whatever. We take the same consideration when it comes to borrowing a friends car or renting a boat or vessel of any type. In general the "buy down" or supplemental insurance is a profit center for those trying push you to pay.
In our case our personal liability insurance will pay for anything we do not intentionally damage. Research your non owned vessels and vehicle coverage. We would decline it and be prepared to pay the $6K if it came to it just like our own boat. Factor the amount into the total trip cost. If you do not end up paying or owing it. You are ahead.
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