Right, a couple of answers to your question MC
My mum is 61, and although slightly mental she generally has her wits around her. Ironically, she took it out of a bank in one 15k go as she is not allowed so much money in her account. She never counted it, and it stayed in the same bag ever since. Just hidden, I have let my mum know now about safety deposite boxes, but never the less.
She last sa it hen packing for a holiday when she had to retrive a suitcase, now whilst she was on holiday my sister was looking after the house, alone for 2 weeks, one of the carers came in and said she saw the empty bank bag on the coffee table with her other items, i.e. phone, wallet bag etc.
I doubt the insurance company will want to know about it, don't know if your covered with family members stealing your stuff.
It has not been thrown out by accident, not sure how the legal systems works, if my sister has stolen it, then mum reports it to the police and my sister is found to of taken it, is it still my mothers choice if charges are brought against her?