How do these things happen?

In a house containing a father, mother, and 4 big kids…. how do things like this occur without anyone taking notice? Yes, it’s red.
Yes, it’s permanent.

Yes, that’s travertine.

After a combined effort involving both parents and 2 of the big kids, and a pack of Magic Erasers, it is no longer red, but a soft pink that we hope will one day fade. I don’t remember the big kids being quite so exasperating. Is that because they weren’t, or just because I don’t remember?