Sorry Scott gotta call foul on your recommendation. Weber CS has warned emphatically about this. That lower end is NOT designed to handle that much reflected heat. Also for the record the grates ARE porcelain coated CI. It is done using a new process that embeds the porcelain into the cast iron not just a coating. I have used Weber CI grates brand new out of the box with no special treatment and have had no sticking. They DO WORK as advertised. Seasoning does improve them a little but is certainly not a necessity. Anyway HUGE CAUTION do not put foil on the grates and ramp up the heat. I ruined a firebox on a Genesis doing that trick.
You know LMichaels, I'm really not sure why you have this need to toss darts my way at every opportunity, but regarding the foiling to clean, that was Phil Harchers own recommendation. Look it up. I'm sure you will likely argue with him too, even though he's a Weber rep, right? Why don't you track him down and set him straight, OK? Again, this is from a totally cold grill, and you end it promptly. I do it on my 670 too, and the 4000 before that, that still runs like new 17 years later. I guess the Genesis series must have been the weak-link, as it couldn't possibly be you, right?
Obviously, you ran it too long if you ran into a problem, which wouldn't surprise me, so I can understand why Weber emphatically warned YOU to stay away from the grill. However, for those who pay attention and aren't easily distracted won't have an issue. Again, direct your complaints to Phil, and leave me out of it, OK? Or, maybe you should report him to the mother ship to protect mankind.
Second, Weber could stick a a few flakes of gold in the molten cast iron, and call them gold grates if they thought the marketing ploy would help, BUT they are NOT the traditional porcelain coated grates you see on the Spirits and old Genesis's. I HAVE plenty of experience with those, and know the difference very well. You must not. These grates WILL rust, and behave just like CI, so if there is indeed some porcelain in them, you sure can't tell, it's definitely not a coating, and it certainly doesn't make much of a difference. If they act and behave EXACTLY like the traditional CI grates they've always had, and most importantly WILL rust, then they need to be seasoned, thoroughly, correctly, and regularly - Again, just like Phil recommended.
Lastly, you are entitled to your opinion that YOU think running the grates right out of the box is fine, and I'm sure many people do. I'm glad it works for you, but the OP is reporting sticking problems, and extra seasoning will only help. Why are you trying to suggest otherwise? It's pretty clear that instead of helping the guy, you'd rather find fault with him, as it couldn't possibly be the grates, right? Since when is extra seasoning ever a bad thing? You make no sense?
So again, what's your point? Just a slow night at the homestead?