Ambiguous Signage

At school there are these signs posted on the walls everynow and then. When I first got to Colegio Maya I spent over a week trying to puzzle out the meaning.....

Ummmm......  awkward threesomes on the roof?
                      please hold hands with people with briefcases?
                      gay couple and third wheel in the relationship?
                      please stay together under volcanoes?

I was very confused. Finally, I asked around and apparently this sign means that you are standing under a beam that can protect you in the case of an earthquake. (I mean that is obviously what that sign says, ha)