Idols saying stuff on Live

Hello

Uh ok so before I start I want to say I KNOW this will seem parasocial and really not that big of a deal but genuinely I’d just like to know..

Are idols not allowed to wish fans happy birthday or something on live?? Yesterday aespa’s Giselle went live and I was commenting “Hi can u say happy birthday” and I noticed some other fans asked the same thing too (to say happy birthday) since the live was a Q&A

I joined when the live just started where there werent many people so I doubt she didn’t see it.

To be honest I know it is not a big deal but I have been to many of their concerts but never managed to secure a video call either I kind of wished she just said a simple “happy birthday” without any name dropping 😢 but she didnt, so I wanted to ask in here is there like some kind of rule where they cannot say it or is it just her personal preference?

and how does one secure video calls… I tried the chinese fan call apps but didnt win/cant pay at all

I can read chinese so language is not the problem

Thanks 🙏