Indeed, in spite of what experts recommend on entire check tipping, guests think differently. Here are some internet comments about tipping on the wine component:
“I like to drink good wine, but I don’t tip 20 percent on the cost of the wine; whether it’s a $50 bottle or a $500 bottle, I’m still getting the same service.”
“In any case, the restaurant marks up wine so much more than food, I feel justified in leaving a smaller tip.”