If I go to a brewery for a pint (brewery, not brewpub) there's a tip line on the credit card receipt. I've been to a couple wineries for a glass of wine...And n

If I go to a brewery for a pint (brewery, not brewpub) there's a tip line on the credit card receipt. I've been to a couple wineries for a glass of wine...And never seen a tip line on the winery recept. Can anyone explain this one to me?