Sakura can't just show up at the last second panting every time though xD I think Ino can convince them a few times if necessary but the more they don't see Sakura with her in the evening, the more they're going to be curious. As a last resort Ino might reveal that Sakura has a secret lover, which her parents will surprisingly be cool with I bet. Sakura's a young woman and is cutely hiding the identity of someone she cares about, then they speculate. Sakura's mostly with Kakashi and they don't see her with anyone but him and Ino, so they'd think Sakura's REALLY GOOD at hiding their identity. It can be a funny spin to a bad situation.