As is so often the case, this is already a solved problem in Japan. When a package arrives, I'm alerted to its presence when I RFID my key to open the lobby door. Then I RFID my key again on the package locker and the locker with my stuff pops open.
The issue with lockers filling up too quickly or packages sitting in them too long is handled by the shipping company, which has sufficiently good customer service to contact me about re-delivering items that aren't reaching me. Also, my neighbors would be mortified if their deliveries ever inconvenienced someone else in the building, so it's somewhat self-policing in that sense.
The amount of over-engineering that goes into overcoming the shortcomings of customer service and lack of basic etiquette in America is amusing and sad. Amazon seems to be an emerging leader in finding solutions for social breakdowns that could be easily solved if people cared more about doing a good job or about extending basic courtesies to their fellow citizens.