I have a digital keypad entry way (this one specifically, although it was $199 when I bought it). It's connected to my home automation system. I've thought about setting up a number for the postman to leave packages inside solely for him, because I can track who and when a number gets used. Haven't done it yet and I probably wouldn't trust a random mailman with the number to my house, even if I knew who was using it and when. This sounds like an interesting idea, but I doubt people will go for it. I just hate keys and like having a number pad entry. It's also nice for pet sitters/maids (never had a maid, but I imagine it would be nice for this) so then I can just give them a temp entry number that is deleted after they are done.