Eh, there would be a very easy way to get rid of most of the guys who only visit the library to see her: She just need to start dating Toiri publicly. Most of the guys would lose interest if she was in a relationship already.
@Kaarme yeah but then those jealous guys would try to murder Toiri and when that happens, we will have a murder case, in which Yuriko would be overexcited to solve it...