Black and white... Useless??

We have a system here in Music Faculty: If you want to use an empty room, book the room in BLACK AND WHITE  before you can use it. Well, that's basically what we did. This afternoon my friend booked the room from 2pm to 6pm. Somewhere between 3pm to 4pm one of our lecturer came in and say: " I asked my student to come here for classed and I planned on chasing all of you out." Why, That's just like so not fair... We have black and white and you don't. Fine. It's ok. We still have lots of other rooms to use. It's just that whether it has a piano or not. Is Black and white not important anymore?