hyeri is not serious.
she does not go around trying to kiss everyone because she's serious, she does it because she's the complete opposite of serious and just likes seeing people squirm. she'll do it for the laughs, for the attention, and for the shock because no matter how many times she pulls this stunt, it still takes them by surprise even though they should know better.
hyeri thinks she can just go around kissing whoever whenever she wants without any real reason.
this is why yura never lets her plant one on her, regardless of whether or not they're in public or being filmed.
because hyeri is not serious and yura wants her to be serious.