When I first got to Shanghai, I kept seeing these stickers on the back of all-wheel drive vehicles, round yellow stickers with a picture of a ferocious roaring bear on them that said:

熊出没注意

I always thought this was something like "The bear came out and I didn't notice". But what that was supposed to communicate was always a mystery to me.

This month's 读者 (Du Zhe) had a short little explanatory article about this phrase, as if it were written just for me. It turns out that there is a region in Japan that is famous for their small brown bears; but these bears were getting hit by cars so signs were put up to warn drivers about the possibility of, basically, bear crossings. Then saving the bears turned into a hipster cause, so the stickers became popular, even in mainland China.

So knowing the real meaning of the stickers hinges on being familiar with the phrase 出没, which means "coming and going". Therefore: "Bears coming and going: Be attentive".