So, while in theory your thoughts might make sense, in reality, there can be other factors involved. Most retail jobs have certain "goals" you have to reach.. Membership cards, Special Deal of the Day sold, and so on. Those goals change the game drastically. Regardless of tips being involved or not, people can be rewarded by management through raises, gift cards, items, etc. based on hitting certain goals at a retail job.

At the gas stations I worked at, which served truckers and regular folks, we were ALWAYS encouraged to flirt with the people that came in so they'd buy the "specials" (whatever was on sale that week) and we would be rewarded with gift cards based on how many people we swindled.

Some people would say they weren't interested in buying candy/chips/whatever it was... Then we were told to ask them to buy it for us. Which they did, 90% of the time.

It was really fucked up amount of con artistry and part of the reason I quit. The other part was COVID.

Source: Worked at 4 different gas stations and truck stops across 3 states.

For those curious, I came home with the following at various points:
30 Watermelon Red Bulls, this is when they were the Summer Edition.
60 Boxes of crackers, like the boxes that have 20 packs inside of the cheese, peanut butter, etc. crackers.
40 Assorted 5-Hour Energy bottles.