I certainly agree about getting the weight off the tires. The new super sticky summer tires will flat spot slightly in about a half an hour after parking. I have AD08R's on an EVO 8 and my own hunter balancer. I had mounted these up on brand new rims, balanced and everything was fine. Car sits a lot (9K miles in 12 years), so took it out for a spin some time later and tires were horribly out of balance. Got better and better as tires warmed up.
After that I tried balancing fronts again as soon as tires were fully warmed up, they were still spot on. Let car sit for about 45 minutes and tried rears. They were already calling for another 1/4 to half ounce on both sides of rim.
Those are super sticky, so they are an extreme case, but I'd guess the stock summer tires they put on these days would not be too happy about sitting in one spot for 3-4 months over winter.
Thought about getting a set of these for cars driven little, but also want the ability to get in and go without jacking down car with weight off tires.
I would also recommend never taking a car with the new type summer tires somewhere to have them balanced. Heat them up real good by driving and immediately take them off the car. Put them in a truck or other car and drop them off to have them balanced.