If you add a new device to UCM and then associate it to the JTAPI user, then true, you would get an event. Usually it's impractical to associate every phone to a JTAPI user, and will exceed performance limits at some point.
Not to mention that would have to be a part of your provisioning process for every phone: no exceptions.
Association limit for phones per user is still 2000?
Thanks for the clarification, we were trying to figure out from the docs exactly what would trigger that event.