The requirement to swipe your campus card again upon returning from the restroom serves as a security measure. It is implemented not only to ensure the safety of library facilities but also to prevent unauthorized individuals from occupying the limited resources available to STL users. Additionally, our student workers may not be able to recognize every user, and the card-swiping process helps us verify and authenticate library patrons. Hence, every time you exit the library, regardless of the duration, you are required to swipe your campus card for re-entry.