I'm leaving soon luckily. I work in a very small private summer school, we don't have our own rooms and there's no staffroom, just some chairs in reception.
There's a library but they often have lessons in there so you can't just go in.
I've been placed in one particular room over the next couple of weeks. We get an hour unpaid lunch, but people just walk in and out as they please even if it's your break.
I'm not 'senior' enough to put a do not disturb sign up or anything.
I don't mind if it's once, but on Friday I had people come in 4 times in an hour when I ate in my classroom.
I can eat outside to avoid this but can't afford to go to cafes every day.
Maybe I'm overreacting but I don't feel like I can ask people to leave me alone. It's just annoying when they (other staff) see it's the break time and that you're eating and they keep bursting in the room to talk to you.