Shoot, they need to paint Allah inside all the port-a-potties, provide Muhammad toilet paper and put Muhammad screens in all the urinals. and perhaps to show cultural support, there should be bottles of camel pee handed out.
The place of sajdah mark is more subtle. A dhimmie could walk by it and not have it removed. The only ones offended would be the true believers, and it would stay up long enough for them to see it.