"Black labs", need to go to lab everyday
I recently joined the master program and a lab colleague (japanese) told me that there is a rule about having to go to the lab everyday from 9am to 5pm. So I asked, what happens if I don't have anything to do at the lab? She told me that there are times where there is nothing to do and there will be people sleeping, reading or even playing videogames but we all go to the lab everyday in case someone needs help or has a question.
I started going to the lab everyday and indeed everyone goes to the lab but most of the time everyone is bored, doing something unrelated to research or just chatting. There are people who do experiments but is not like they are teaching anyone, everyone is on their own most of the time.
My supervisor hasn't talked to me about this. Not even mention it and before this colleague told me anything, I wouldn't go to the lab so he probably noticed that and still hasn't said anything. I'm the only foreign student in the lab so I don't know what other foreign students did before me.
My question is, is it mandatory to follow this rule? Are there any consequences like not graduating? Would like to hear your experiences if anyone has gone through something similar.