This reminds me of a reddit post from a while ago. Dude is going to a university in the US. He's randomly contacted by campus police to let him know that a student has taken out a restraining order on him. He's a graduate student, and the student who took out the restraining order is from one of his classes that's typically for undergrads. Other than sharing that class, he doesn't know the student. Never even spoken to them. He's on a student visa, if he's expelled, he'll likely be deported. He's not allowed to speak to the student and campus police won't even tell him why the restraining order is in place.
After doing some investigation on his own, he finds out the student is dating one of his roommates, who he also doesn't know very well. The roommate is stalking the student, and another roommate is helping the stalker.
The student who took out the restraining order had seen him with the stalker at some point and, because the class they share is typically for undergrads, assumed he only took the class to keep an eye on the student for the stalker.
He was able to go to his graduate advisor about it and luckily it all got cleared up, the student withdrew the restraining order. But his whole academic career was nearly derailed because a random person was able to take out a restraining order on him with zero direct evidence, and there was no established means by which he could defend himself.