Many mobile applications enforce certificate pinning in order to make a man-in-the-middle attack difficult to accomplish. However, with a jailbroken/rooted device, it's possible to disable the certificate pinning on the client. For example, by using SSL Kill Switch on iOS.
A previous question asked how to "prevent bypassing certificate pinning." I understand how prevention is effectively impossible, since as long as the client has root on the client device, any prevention is limited to "security by obscurity" and reduced to playing a cat-and-mouse game.
However, I'm interested in whether it is possible to detect, from the server side, when a client has disabled certificate pinning.
1) Is it possible, using only low level SSL functionality, to detect when certificate pinning has been disabled by the client?
2) If not possible with low level SSL functionality, then is there some information the server could require from the client in order to prove that certificate pinning remains enabled?