小费罐，根据告示是没有义务给的。

Tip jars, according to Post, carry no obligation.

youdao

我可否装着已经掷了一些散钱在小费罐里？

Can I just pretend I already tossed some change in the tip jar?

youdao

小费罐就在登记薄的右边，当侍者用收银机为我结账的时候盯着我。

The tip jar—it sits right next to the register, staring at me as the barista rings up my order.

youdao