This "we need to restrict your private life for your own well-being/security" reminds me so much of the worst parts of Seiyu Radio no Ura Omote. Given that there's upwards of like 30,000 female idols in Japan (estimated) and there's news stories only a few times a year of any significant stalking, much less harm, it's just not as statistical of a danger as they made it out to be.
Which, no doubt, someone is already seeing that and is being big mad I wrote that and bringing up incidents that have happened and already typing out how dangerous it is (wouldn't be Mangadex comments if that weren't the case). Yeah. Like I said. Statistical outliers.
Realistically, her agency would be much more apprehensive about her dating and that being found out than her going to a school festival.
But, hey, whatever, the plot needs a complication for drama purposes I guess.