Kacie came across like whiny little girl to me. And her over-the-top, 'trying her darndest to conjure up tears' in the limo act fell flat. I'm sure she was upset he'd sent her home, but not to the degree she was trying to portray that she was. Her crocodile tears weren't fooling me no how.
"You mustn't be afraid to dream a little bigger, darling"
Her tears seemed genuine to me. This appears to be a young lady who thinks she has to make everyone happy. When Ben "rejected" her, in her mind it was because she did not make him happy. She even said in the limo words to the effect of, "What did I do wrong?" I think this kind of thing really pushes her emotional buttons, and she had a genuine mini-meltdown. Besides, I have read that the producers keep driving the "rejects" around, poking and prodding at them emotionally until they break down.
Parents who are familiar with this show certainly know that marriage does not result quickly even when the "engagement" happens. No reason to take it seriously. Just entertain the bachelor, be cordial and go with it. Production has a hand in pushing the parents to talk about what we see, as well.