I was blanking pretty hard when I wrote that and meant to write RDP while thinking of TeamViewer. Need to post stuff less late at night

For desktop windows this is not true. A remote sign in will sign out the local user and vice versa

Remote access with continuum/connectwise, TeamViewer, etc gains access to the screen including for control but doesn't normally black out anything locally.

If its in a common area with speakers, anyone can both see and hear anything done on the machine.