Totally made up and arbitrary example but it would be like if Starbucks started serving some widely popular menu item based on a recipe from a competing chain. They already have a huge loyal customer base that's coming into their stores all the time, so it's more convenient for these people to get this new item at Starbucks since they're going there anyway, but Starbucks didn't come up with the idea or recipe, they just saw that it was popular elsewhere and knew they could leverage the convenience factor to get people to buy it from their stores (which people were already coming to) instead of going to a second store for it. That's not really ethical competition.