Is there a way to prevent the screen mirroring or one-touch mirroring features from being changed or disrupted by a second registered user?
As part of the normal operation, the TV always accepts the latest input control when using either of the mirroring features. So it will always display the content from the last person or registered device that attempts to connect to the TV. There is no way to lock the TV to one user or registered device.
NOTE: One-touch mirroring is only supported on certain models of Sony® TVs and Xperia™ smartphones.