This message applies just to those students registered for these three labs.
I just checked the seating for the labs and found (I am sorry to say) that the three labs 01, 04, 05, are slightly overbooked. There are only 20 terminals in the lab, so the overbooking means that some students will need to share. This isn't ideal, so you might wish to change your lab. Some labs are almost empty: for example L09 has only 2 students registered so far. If you switch, you'll get more attention from the instructor.