I just swapped out my run-flats for snow tires on my wife's car. The tires I swapped on were already mounted/balanced previously before removal. Is there any need to get them balanced again (or do anything else) now that I'm swapping them on for the snow season?

Obviously with the snow tires I'll have no spare. I do have the Platinum Service Agreement on this vehicle. Does anyone know whether Lexus will cover the cost of getting the car towed to the nearest dealer should I get a flat? I know the warranty covers towing to the nearest authorized dealer, but I wasn't sure if it was covered under such circumstances.