You don't need to bother unless someone asks. Seriously, when people here see English on a poster, t-shirt, or in an advertisement, they ignore it. It is as if you were actually going to read itune's terms of use. Nobody does. Might as well be in Russian.
When I pointed out mistakes in English at my old school, I mentioned it to my co-teacher, and she said "Yeah, I know that is terrible, but if I tell the principal, I have to find the money in the budget to fix it and take over that "project.""
For me, I have a round thing in the back of the room that proudly displays "Ten Little Indian Boys" song, and I am 1/4 native american (actually more, but it is hard to count the extra that is more than three generations back as they came from everywhere). I really hate it, and so I just covered it up with a talking tv that does nothing. Tada! Useless tech fixing useless English. What a splended world!