The long and short of it is, regardless of what the internet lawyers tell you, if you take money for a product and that product does not arrive to the buyer or arrives in significantly other than agreed condition due to shipping damage, Somebody is going to take a loss and it's not going to be the buyer unless they happen to be some saintly character. You as the seller will wind up loosing one way or another, unless you can successfully file a claim with the shipping carrier to get reimbursed, or have actually purchased real 3rd party insurance coverage & are willing to eat the deductible.
I do distance selling for a living and know very well how the whole "I don't need insurance" thing works out.
We get it all the time, usually from other cheapsakate resellers trying to ship on their shipper account & not wanting to pay for insurance, claiming that they "Have their own insurance coverage" and sometimes even demanding no insurance in writing on their Purchase Orders.
In the past 2 decades I've never once seen anyone that demanded no insurance or claimed to have their own insurance coverage be willing to accept the loss if something arrives damaged or never arrives. They will without a doubt start trying to do a chargeback, refuse to pay their invoices, threaten to sue you etc, try to ruin your reputation, try to make a fraud complaint against you, blackmail you anyway possible to get you to pay for a replacement item or refund them.
That's why we tell them sorry, it gets carrier insurance or we cancel your order, no exceptions. When we ship, our prices include insurance in the shipping charge, if we are shipping on their account, carrier insurance is mandatory for them to have selected.
You can argue till you are blue in the face about that somebody agreed not to pay for insurance and accept the risk, but in the real world that doesn't hold water & buyers never own up to it. So why put yourself through all that trouble?
If you are shipping something, just set the shipping price to include insurance for the sale price. If you are including shipping in the price (the whole "free shipping" BS), then make sure you calculate the price for the item based on insured shipping cost.
It's usually like 0.64% or less depending on carrier and total amount.
I understand some people are such reprobate cheapskates that an extra $20 to insure their $3000 purchase is the end of the world.
For those people you simply have to tell them No, it's for your own good and that is that.
Now if it's something that's so cheap you don't care about taking the loss if it never makes it, well then go for it, but usually that is under the $100 / $50 minimum insurance coverage most carriers offer by default.