Thanks for your comment Robert. May be you are right. Whether the interest will be enough or not actually depends on how many customers you have and the amount of money accumulates at the bank. But your suggestion does make sense. Thanks.

Bill, I am not sure if I was clear enough about the business model. What I am thinking is not a revenue based on individual lost key events. The revenue will be based on the interest of the money you collect from customers or a registration fee may be as Robert mentioned.

How about other items? Driving licenses, mobile phones etc. (you can place a small sticker on them) The important thing is, will people care to deposit a refundable amount for a service like that. Need comments.

Thanks