Gosh how awful to have the next client walk in your session

I see my T in private practice (at her house) so fortunately it is very quiet and she doesn't need anything on her door. However, I saw both prior ts in noisy environments and even though both of them put a 'Do Not Disturb' sign on the door, with first t someone knocked on the door (t went and spoke to her, which annoyed me) and with second t someone actually walked straight in, realised their mistake and immediately went back out. It was enough to disrupt me for the rest of the session though.

It is important that the environment is secure but not all ts would probably be happy with a lock on the door.