I find that really unlikely.
I mean, for starters, they had her body and knew it was her body in storage. That doesn't happen if they don't have IDs attached to the corpse. I find it unlikely that the hospital wouldn't be ringing the family like crazy because of a body they want to unload. Especially if they have the paperwork showing that she'd checked out. There'd be no reason not to almost immediately say "Hey, actually, we found her right outside the hospital dead, sorry for your loss".
I'm guessing an obvious fuck up killed her like 10xing her insulin dosage by mistake. Or administering something other than insulin.
And it wouldn't surprise me if, conveniently, 17 or 24 months just happens to be the retention policy for medical records.
This was in California, where the law [0] is 7 years minimum, potentially more if the patient was a minor.
AFAICT every state wants at least ~5 years of retention.
[0] https://www.law.cornell.edu/regulations/california/22-CCR-72...
Front-desk has a signed waiver? Good luck proving that it was the person on shift at the time who forged it, she doesn't remember what happened a year ago, and the existence of the fraudulent waiver isn't proof that she authored it.
Nobody's responsible, and nobody's accountable. There's a legal requirement that someone at the hospital should have done their jobs, but there's no legal requirement that forces someone particular to do them.
She checks herself out (given that she called about leaving I find it reasonable to think she might have), goes to the bathroom and arrests in a stall but is not discovered for a while.
The family is looking for her, the hospital correctly notes that she had checked herself out. Eventually her body is found. She's not a patient since she checked herself out. Somehow it fell through the cracks about notifying her family, or perhaps she didn't have ID on her and the body was sent as a Jane Doe.