Notice on the New York MTR:
jìnzhǐ shǐyòng huábǎn 禁止使用滑板
("the use of skateboards is prohibited")
The problem with this notice is that what's being prohibited are hoverboards, not skateboards. In Chinese, the former would be xuánfú huábǎn 懸 浮滑板 (lit., "suspended skateboard") or qìdiànbǎn 气垫板 (lit., "air cushion board")
For the whole story and the source of the photograph above, see Nikhil Sonnad, "The New York City subway has banned skateboards—but only if you read Chinese" (Quartz, 3/16/16).
[Thanks to Mark Mandel]