I know that the combined effects of spellcheck and of a growing population where English is not the primary language have caused spelling to become a lost art. I think that it always used to be that sign painters knew how to spell, but the DIY world has also caused this skill set to erode.
Witness the following orthographical missteps:
The florist on the corner sells panzys, marry golds, and for the fall something he views as cock's comb.
The local nail salon now features a special from Monday through Wednesday---manicure and padacure for $35.
The local lumberyard/woodworking store lists, among their products a quantity of sadles for sale, and I'm thinking they meant saddles for your door/threshhold.
And yes, I did just run spellcheck before posting, jic.