Punctuation Plunder

Does anyone else find this sign ironic?  The "Writers Store" apparently sells everything writers need...except for apostrophes.  Perhaps the "Writers Store" doesn't believe in plural possessive nouns.  Any way you slice it, I just can't trust a company that boasts itself as a "premiere source for writing" but doesn't have a basic command of punctuation.

I am by no means a perfect writer, but if you are running a store for writers, you probably should be pretty well versed in the ways of the apostrophe.