Old ploy of the Left -- I was in grad school at Boston University in the 70s (the era of Vietnam and student radicals), and they got as many as a couple of bomb threats a week for a while. (Temping summers, I sometimes worked in an office building that got them.) They certainly didn't get national coverage though; I don't even recall that they got local coverage.
After the first few, the professor/office manager when notified would just make the announcement and tell students/workers they could go outside if they wanted to while the fire department checked the building, but fewer and fewer people bothered.
Bomb threats: just another liberal tactic to get out of work