Are you supposed to tip at Walmart curbside?

Are you expected to leave a tip when using the curbside pickup service at Walmart? It's not a traditional service industry setting like a restaurant or hair salon, so it's not immediately clear if tipping is customary or even appreciated. On one hand, the employees are providing a convenience service that saves you time and effort, which some may argue warrants a small token of appreciation. On the other hand, Walmart is a large corporation and the employees are being paid by the company, so some may argue that a tip isn't necessary. What's your take on the matter? Do you think it's appropriate to leave a tip at Walmart curbside?