This is spot on.

Figure out what the scammy stores are in your neighborhood, and don't go there. Figure out the restaurants that constantly get your order wrong, and either check on it before you leave, or don't go there.

Also, keep an eye on the register and if something doesn't seem right, just say you don't want it. I picked up some unlabeled asparagus once and when it rang up as $7.99 I just said I'm sorry, it's too expensive, I'll put it back. Problem solved.

NEVER feel guilted into tipping what the machine requests.