One of the people behind this ban said that he does not want to need a high school level education in order to "find a restaurant." Are you serious? Then go hungry! If you can't leave your house without being attacked by punctuation marks, don't go out. If the presence of an apostrophe reduces you to a complete idiot (instead of just a partial idiot) then don't go out and for God's sake, don't breed.
If people with a high school education or better are the only ones who know how to read the difference between plural and possessive, then there is a lot to be desired in Great Britain's elementary curriculum. (See? Right there: the curriculum belongs to Great Britain. How difficult can that be?!)
Does any society benefit by dumbing things down for the lowest common denominator? That would be like intentionally rotting the teeth of the few Brits who are acquainted with a toothbrush, so that those who qualify for the Big Book of British Smiles won't be the only ones with a horrible dental situation. Or like taking out the entire Theatre District in London because some audience members didn't understand a show playing there.
I would also argue that it is far cheaper in the long run to educate people than it is to go around removing a little punctuation mark from every sign. Ridiculous.
If the leaders in Birmingham devoted as much time to dental care as they do to this assault on the Queen's English (That's their Queen, their history, in case you were unaware...) then at least the population would be a bit better looking. Stupid and attractive goes much further than stupid and ugly.
(Yes, I know this is a snarky diatribe, filled with cliches, stereotypes and generalizations. So what? At least it's not filled with cliche's, stereotype's and generalization's.)