Here we go again! Scott Disick, 34, and Sofia Richie, 19 -- we've always gotta remind you of that age difference -- jetted off on another expensive, romantic, inappropriate vacation on Saturday and guess who's probably footing the bill? Daddy Lionel, we imagine!

Sure, Sofia's had a couple modeling jobs but let's get real, people, you can't get all over the world and stay in 5-star hotels, wearing the most expensive fashion labels and eating in the best restaurants on an Adidas paycheck. So we assume Sofia's legendary singer dad Lionel Richie is just paying off his daughter's credit cards each month with all this travel charged on it ... and HE'S the one who said he's "scared to death" about Sofia dating Scott! Then why pay for her to do it, Lio?!!