Or maybe the event happens randomly and you have to visit the place several days until it shows, like it happened with the girl in the library.
I have doubts regarding the hot event in the swiming pool, for example. Is it just seeing the girls naked in the shower or there's something more?
Edit: I had to visit the swimming pool several days at night, until I got the hint to go to Ruby and talk to her, after I saw the trainer talking with the girls (It seems that both events, Barbara's one and this one, happen randomly).