How would you react if you know someone that uses Mangago

Examples are colleagues, siblings, parents, lover, and friends.

I feel like my sister uses mangago because I’ve seen an account by the name she usually goes by. When I saw that name my heart stopped. I was sweating and praying it wasn’t her. I got really scared because if she knows this is my account I can never look at her again. But I don’t really know if she uses it but she has said some things that only happen in mangago so I’m actually thinking she uses it.
How would you react if you found out that someone you know uses mangago?