To me it's not so much of whether to believe her or not, but it comes down more to were her observations correct. Was there really no way to get in? All we have is her word on it, so it is much more likely that she just missed something about the situation than actual spirits were throwing trash.
Even if the open windows of science at first make us shiver after the cozy indoor warmth of traditional humanizing myths, in the end the fresh air brings vigor, and the great spaces have a splendor of their own - Bertrand Russell