Hey there. I don't work for Lockitron, so always check with them for official answers.
In the meanwhile,
I believe it's Admins, but I don't think it should send a notification out to everyone... Make sure you're using your own individual access token etc, and that your SMS access is set up as an individual app on the API page.
At any rate, there's no notes as to whether or not this is by design.
Yes. In "Locking and Unlocking", it states:
This method will lock or unlock the user's door. It blocks until locking/unlocking is finished. If the Lockitron is asleep, it can take several minutes. Failures return standard errors.
This is followed up by the "Pending Action" section:
This method allows you to cancel a pending activity on a Lock. Pending acitivities are those activities on WiFi Lockitrons which have yet to be carried out because the Lockitron has not yet reconnected to WiFi since the command was sent.