Chazal say that the reason we dip the karpas at the seder is so the children will ask (Pesachim 114b). Meaning, it will spark their curiosity and they will then end up asking other questions about the evening, leading to discussion about the Exodus (see Tosafos to Pesachim 115b s.v. kedei).
However, a major theme of the evening is being benei cheirus, free from slavery. Some understand this to mean we should act like royalty or aristocrats, which is why we lean. Some say that this is also why we clean the house and make the seder table look beautiful (see Rashi to Pesachim 99b).
I have heard from a contemporary Rabbi that this is another reason for dipping karpas. It is "royal" to serve a vegetable dip as an entree. I didn't see this in any classical sources. I was wondering if it appears anywhere?