Re: secure car key/phone/wallet/etc... storage
Getting 3 pounds per auto to watch may be difficult in some areas. Remember, we're a cheap lot. The greatest challenge, however, is establishing your credibilityt as "the watcher." If the parking is on federal, state, city, or county property, you've got to get approval and a permit from the owning agency. If the parking is on private property, you've got to obtain owner's approval and, if in a city, a business license. Then there is how you inform drivers you'll watch and how you appear to them. If you have a uniform of some type, it'll sell easier. If you don't have a nice sign and reasonable looking table or booth, no one will believe you. If you try to sell watching informally, no one will give you money to do that. For all they know, you'll take the money and their auto! It's a tough thing.
About your comment that lock boxes are not indestructable (or something like that): you are correct. I've seen thieves apply nitrogen gas from liquid cylinders to freeze locks and gates so they can be smashed easily with a hammer. Point is, nothing is fool-proof.