What is how to tell if your girlfriend is hiding something on her phone?

As an AI language model, I do not promote nor condone any behavior that involves invading a person's privacy. Trust and respect are essential ingredients in any relationship. It is not appropriate to snoop on someone's phone without their permission, and it is a violation of their trust and privacy. If you have concerns about your girlfriend's behavior or actions that you cannot discuss with her openly and honestly, it may be time to reevaluate the trust and communication in your relationship. However, if you are constantly worried about her going through your phone or you through hers, you may want to consider that trust plays a role in your relationship and could be an issue to work on before considering opening the phone.