Grocery Store Samples?

How is this any different than eating at a non-chain restaurant or at someone else's house? Other than the fact that you're eating very little so guessing probably isn't going to be a problem? If you eat YYY at a restaurant you have to guestimate the calories, right? You aren't going into the kitchen while they are cooking and weighing all of the ingredients. Just do the same thing. Ate a bite sized sample of YYY at the grocery store, just find an entry on MFP that seems relatively close and ballpark what fraction of a serving you ate.

You can't be accurate, just be reasonable.

The grocery store I shop at most has samples of produce often. Squares of cantaloupes, slices of apples, strawberry slices, etc, speared with toothpicks. They are legit samples; when the fruit isn't ripe the samples are not very good. When they are ripe, I could stand in front of the melons all day. But I don't. I buy one and take it home and weigh what I eat at home. But when it's just small samples of produce, I log it as one of the fruits in a small amount that seems reasonable. I rarely try other samples.