What unusal behavior would alert school's system administrator from mining bitcoin? I work in a lab and I have full access to the lab. I often leave my old laptop in this lab to do computational stuff (for lab or for my own stuff). If I want to mind bitcoin using this setup, what unusual behaviors will alert the administration of the school's network? Will there be a huge outgoing traffic? Does it require some ports to be opened?
I know it doesn't answer your question, but: don't do that.

Time to mine on regular computers, even with strong GPUs, is long gone. If you don't have powerful ASICs, forget mining at school computers.