my school installed this one extension called GoGuardian that allows teachers to look at your screen at anytime and do stuff like close ur browsers the only way around it is to reset the PC (which is possible since my High School uses Windows and not Chrome) but the downside is that u loose the connection to the good school wifi, forcing u to use the free one which sucks i did also exaggerate a bit, my school does block websites but not every single one, elementary/middle yes. but it still blocks a fair chunk of stuff i'm so glad that I have a proper laptop