I anticipated twins with The school directory sync system I made for a small District (sub-5000 enrollment). I appended a random two digit number to first initial, last name (EAnderson96). So far none of the parents who have "weaponized"(1) the naming of their children have managed to break it since we brought it up in '99.

(1) Hypothetical John Smith and his siblings Jane Smith, James Smith, Janet Smith, Jack Smith, etc. It's a bit infuriating how many parents do this. Amusingly I've had O'Brien and other apostrophe-contsining names with no ill effects (because I sanitize my inputs). In the last couple years, though, I was forced to start dropping apostrophes because we had third-party apps/services we were syncing to that couldn't handle them.