On the left hand side of your screen is the mini log list. If you see students in that list and they are not in your center it is time to do clean up!
Students should never be logged into a center and forgotten...they must be logged out. If you forget you will impact your hours data. Generally, advising offices should not see anyone in this list at all. The majority of offices that use the log in log out feature are Tutortrac. Most advising offices check off that each student has "attended" their appointment during their meeting.
Deciding how your office wants to check off students attendance or choose to log in log out is individual and requires a training conversation.