traditional service industry where their employer pays them $2/hr. YES, but I wish your employer would just pay you. I'm still tipping not going to punish their employer for that but seriously try not to even go to these places anymore.
Other traditional services industries, barbor, nail salon,etc. Yes as appreciation. They personally took care of me so yeah.
Baristas, it any other ipad station. NO. They are paid a standard wage. I might drop my change in a tip jar every now and then when paying cash but that's it.
Food trucks and other independently owned stores. Generally No. Food trucks are independently owned and not service industry. If they need more money charge more for the food.
Yes! Just do this! I promise you seeing more expensive prices on the menu will annoy me FAR less than getting the check and seeing a surprise 18% "service fee."
Even for point 1 it's just wrong. They should not work there for that wage and if the business needs to charge more money to pay them more then charge more money.
Relying on tips for worker pay not only shifts the responsibility for paying the employees away from employer to the customer but also makes employees getting paid optional (depending on how a random person that walked in feels).
I always ask the person helping me if they actually get the tip money when using some kind of kiosk. A ridiculous number of places "tip out" not only to cooks, but to managers and owners.
If I have cash and I think they deserve a tip, I will give them the cash directly and tell them to pocket it.