For just an oil chance there should be no need to plug the car in, not saying that some update hasn't been released for the software that we don't know about.
Every time my truck goes back to the dealer for whatever nonsense that is wrong with it on an almost monthly basis I am very clear to tell them that the truck has a tuner and not to reflash the pcm and insist they note it on the mechanics work order. I've never taken the tune out of the truck when going back to the dealer and they still honor the warranty on the truck no questions. For that matter, they just replaced the egr cooler at no cost. The dealer knows if you've re flashed the computer so no sense in trying to hide it