This is a really great one, so many layers to it. Seems to me that possessive ' on plurals is just gradually dropping out of the language - people employing the 'if in doubt, leave it out' rule? But why the plural with an apostrophe? I confess I love these. Sign outside a local caff advertised
Teas and Coffee's
I just wanted to rush in and go 'Why? Why not Tea's too?' I always feel there must be a reason for these weird usages - rather than just 'bad grammar' - but even I am starting to admit that some of them must just be random...