(Strip Number 4805, Original Publication Date, 26 May 1987)
Panel 1: A little while later, Michael asks Elly if Lawrence's stepdad is rich. She doesn't think so.
Panel 2: When Mike asks how much he does make, she says that it's none of the Pattersons' business.
Panel 3: She actually looks him in the eye when she explains that it's rude to ask people how much they make because it's an invasion of privacy.
Panel 4: She then thought-bubbles that what we do is we make rough estimates.
Summary: This is a common enough problem, I should think. At one point or another, all of the kids have to be cautioned against this sort of breach of decorum.