The eye-catching new signs at the entrances to the Science Center shouting in all-caps that tour groups are no longer allowed in the building are no joke—the management wants to keep the camera-happy throngs out.

The new policy is a response to complaints about tourists disrupting classes this summer, according John B. Mathers, senior facilities manager of the Science Center.

At times, Mathers wrote in an email, tourists entered the back of an auditorium during a lecture, snapping photos and chatting.

"The addition of another 40 or so non-Harvard persons standing around taking pictures simply creates an impediment that is not needed," Mathers wrote.

The signs also state that individuals may not take photos or video inside the building, reminding visitors of a longtime University policy prohibiting unauthorized photos in classroom buildings.

That didn't stop us from taking a photo of the sign.