We also have a couple of August Smart Locks.
The system has worked well in that it sends the invitation to the guest automatically,
and that the locks open and close according to the guest settings.
However, as someone else stated, it is not at all clear what the status of any given guest is.
Did they receive the invitation?
Did they install the app?
Is the app linked to the AirBnB reservation?
There should be a simple way for the host to determine this at a glance.
August should have a web interface that shows you all the invitations sent and who has activated.
The app is supposed to do this, I guess, but it does not show any guests until they have completed the activation process.
So you have to send messages to the guest to find out what is going on, which is stupid because the August lock system probably already knows but won't share the information with you.