Most wineries have moved to this model due to the virus. To find the best solution, I sent an email to 20 of my closest friends who have worked in the wine industry. But no, you don't need to tip extra on any bottle of wine you buy to take home. Accidents happen, even sommeliers and wine experts can spill, so if you choose to wear white clothes during the wine tasting, try not to get upset if there is a mishap.
Some wineries have paved walkways and patios, others have grassy picnic areas for tastings, and some may offer a vineyard tour, where dirt and uneven terrain can be expected. To override this behavior, some wineries have implemented minimum requirements for wine club memberships, which generally range from two shipping commitments to one-year requirements. In Japan, on the other hand, a wine professional may politely decline your tip, as good service is expected. Often, your perception of wine (and how much you enjoy it) will change in the second or third sip.
Wineries are wineries, not bars, so drink lots of water, don't drink on an empty stomach, watch how much you consume and keep the conversation at a reasonable level. Wine tasting may seem intimidating, but it's actually a relaxing way to spend the day discovering liquid treasures made by passionate local winemakers. Instead of a tip, these reps probably prefer that you spend their cash on buying their wines. And again, if you loved your waiter and joined the wine club, you're likely to see him again, so leaving them a good tip will mean better service in the future for you.
The situation is similar in Australia and New Zealand, where service workers, including wine butlers, receive a living wage and do not rely on their tips for a living. Tasting fees are the standard operating procedure at most wineries, although some still offer free tastings or tastings refunded with the purchase of wine. No winery host wants to see you fall because you chose to wear heels during the “walk to the vineyard” portion of your wine tasting.