[benjsec]

Perhaps something like a old-fashioned padlock? Anyone can click it shut and then you need the key to unlock it again.

[astura]

Yeah, that's the traditional package box. This is an example: http://www.pe.com/wp-content/uploads/migration/oh4/oh4e3m-b8...

The issue with that is people know if there's a package in there or not, you can't have more than one delivery service come in a single day, and you run the risk of vandals running off with your lock.