Technically, that's a "voluntary" commitment, with the cops "escorting" you to the facility. Medical facilities cannot actually compel you to pay such involuntary "services" unless you allow it. Of course, it's pretty easy to inadvertantly "allow" it...

If you are ever in a situation where you're going to be held for observation, calmly and politely inform everyone who approaches you that you are being held against your will; that you will not physically resist, but you do not consent and will not otherwise cooperate with any treatment. If they ask you to get up on the bed for an examination, "You'll need to make that an order, not a question."

Definitely don't provide them with any billing information. Police will give it to them anyway, but that's on them, not you. Definitely don't give them any insurance information. If they already have insurance information on file and ask you to confirm, tell them that policy was canceled. If your insurance pays anything out for any part of your treatment, they will be coming after you for the rest.

Make sure you inform your insurance carrier that you did not have any authorized treatment during the time in question, and that any billing during that time is fraudulent and shouldn't be paid. Your insurer will love to have your approval to deny a claim.

This won't get you out of charges accrued while the ambulance and hospital are operating under presumed consent (while you are unconscious drunk, or otherwise in an altered mental state, and a reasonable person would believe you would consent to treatment if you could). But, where treatment is being forced on you by a third party, you can successfully challenge the bill.