One time I joined a call after a long night with barely any sleep, eyes barely open.. and the moment I heard, "Camera on, please" I turned it on without thinking only to realize I wasn’t even wearing a shirt! Luckily I reacted fast and turned it off within a second. Somehow no one said anything, and to this day I still don’t know if anyone saw me.
WFH rookie. You always have a zip up sweatshirt or sweater and a hat within reach. Within about 8 seconds you can be camera ready.