Yes, the campus police should lock down dorms based on social media threats, because social media is good place to find out what people are honestly thinking. If my child were at a university, I would rather that they be too proactive in keeping my child safe, and order the lock down, even if the threat was later unsubstantiated.
Campus police must take every threat, whether physical or electronic, seriously. With all of the past violence that has occurred on campuses around the country, it would be irresponsible to take any threat lightly until it has been verified as truly dangerous or not. A few hours of being inconvenienced is nothing to saving lives.
In these cases the authority should use their best judgement to identify whether there is any legitimacy to a threat or whether it is a mindless prank. If there is a genuine security threat then students should remain locked inside for their own protection. However, it is important not to overreact and be sensible when there is no clear threat.
No, campus police should not lock down dorms based on social media threats. These threats should be reported and researched before intense action is taken like locking down dorms. Many things are threatened over social media that are said out of dislike for someone else. These are not always immediate dangerous threats and should only be treated as such if there has been a physical conflict.