Now we come to the real que'stion, when should there be an apostrophe before the last "s"?
It i's the whole crux of the is'sue, if you wa's to a'sk me, and the rea'son thi's thread wa's po'sted in the fir'st place. At lea'st, that's what I gather from reading between the line's.
And shouldn't Brits (Brit's)have that apostrophe too? It does signify the missing letter "i". (and where did the "h" go, enquiring minds demand to know!)