@LygarX that's my takeaway too. Everyone else is talking about her outfit but they definitely seem to recognize her. Someone else mentioned she may have been involved in the parents accident
@Escheron I suspect that Lilith is the daughter of a rich family and, as such, other members of high society would probably recognize her and are probably curious why she's attending Parent's Day as a "parent".
I honestly don't think this manga will ever get so dark as to somehow implicate Lilith in any foul play regarding the parents' deaths.
@Jethzki You'd have to ask Wakame Konbu as there isn't much of anything to spoil about Lilith's past at this point based on anything in the manga itself.
@panzerkampfwagyu I think the main point of this chapter was more to give slight hints about the pasts of both Lilith (that rich people seem to know who she is and are surprised to see her there, implying that she isn't just a servant) and Yuuri (that his parents were a bit distant to him) than it was to be funny but I suspect we'll get more comedy next chapter.
I thought Lilith considering the sort of clothes she'd wear to Parent's Day was quite funny.