I'm guessing only one lights up at a time, and it changes based on the current owner of the control point within the building.
I once was at a hotel named BLU Ocean.
Oddly I found no obvious rockets or lazers.
While visiting Alaska over the summer, I saw a store called 'BLU Outfitters' or something like that in Anchorage. I hope I took a picture.
Guys the world of tf2 and real life are merging. Muffin see if you can rocket jump, now!