My take on Rion is that she got herself in trouble with her agency. The trigger likely was this video in which she appeared to be revealing her real name and exchanging contacts with a random Korean Youtuber. There's probably multiple breaches of contract in regards to her agency in this video alone.
What else did she do in the video that would be a breach of contract? It looked like they just talked a bit.
Was it really a chance encounter where he recognized her as an idol or he thought he was just talking to a random pretty girl? Anybody with better language skills able to summarize what they talked about?