Since some people do seem to accept to tip up to 20% (as per the article), why would they not ask? It costs nothing, so it's basically free money. Maybe the ti

Since some people do seem to accept to tip up to 20% (as per the article), why would they not ask? It costs nothing, so it's basically free money. Maybe the tipping-culture is so embedded in the US that some people find it hard to refuse? Because here in Europe I can pretty much guarantee that people would simply mutter "F off" and tap 'no'.