We already use a similar type lock system in our properties. But it still requires us to log in online and issue an actual time sensitive code that is punched in to a lock, and there is no way to revoke it unless you go to the property (other than it expiring).
I spent months looking for it years ago. Its one of the reasons I was drawn to XPed because its something I actually need in my businesses as well.
RYG Price at posting:
3.5¢ Sentiment: Buy Disclosure: Held