[coldpie]

I think it's much more likely that s' is and has always been incorrect, but the error is so frequently committed that it has become "correct". Language does evolve, after all.

Snark: Given the current rate of apostrophe-abuse, I look forward to the apostrophe merging with the S at the end of words to form a new final-S character, which eventually usurps S entirely re'sulting word's that were 'spelled wrong becoming correct, and creating very weird form's of po's'se's'sive noun's: Jame's''s.