Doubling and even tripling of coupons at the grocery store seems to be a regional thing. I’ve never seen it in California or around Chicago, but it seems to be common in the East and South (eg: Virgina, the Carolinas, Georgia, etc). Friends from Connecticut speak of it. Last June, our very own Wesley Clark spoke of it being done in Indiana. And of course, it seems to be legendary at Kroger.
Why isn’t it done in CA?
About Consumer Promotion Offers
WAGs - Because they choose not to do it. Because the manufacturers won’t allow it in California. Because there is too much coupon fraud going on. Yadda, yadda.
It cuts badly into the store’s profits. You need to increase sales to make up for the money you are losing by doubling. With a regular coupon, the store gets a little more than face value, so they make a little extra redeeming it. With a doubled coupon, the end up losing the difference between what they are paid for redeeming and the amount they are reducing the prices.
Given the choice, the stores would rather not do it. But if a particular grocery starts, others in the area have to join in so as not to lose sales.
It is done in California, at least down here in the civilized part. 
I have shopped the local Ralph’s with double-coupons often in the past. I don’t see any current promotions in the paper, but they are there on occasion.
Both Ralphs and Hows (the guys that used to run Hughes started a market after seeling Hughes to Ralphs) both double coupons. I think Albertsons does, but I don’t shop there.
Double coupons are not an infrequent promotion used at grocery stores in Southern California. I’ve seen them used here for over 20 years.
I rarely use coupons because I’m just not that kind of a guy.
It depends what you mean by “around Chicago.” When I lived in Peoria, double coupons were common, and once one store started that, many others did too. The same as here in Chas., SC.
Of course there are some items that stores won’t give double coupons for and in fact I don’t even think that there are regular coupons for alcoholic beverages or cigarettes.
California has some restrictions on how much you can discount fluid milk products too.
Marsh and Kroger have coupon wars every few weeks around here. Typically, it’s triple up to $.50 and double up to a dollar coupon. Each Sunday paper has 2 or 3 coupon sections, and the cash registers spit out coupons, too. Some coupons state, “no doubling,” so I wonder if the brands pick up part of the doubling expense. Some of the Krogers have attached gasoline stations, and the register tape has a gas discount coupon up to 10 cents a gallon for gasoline at Kroger. That’s pretty alluring these days, with petrol at $2.20 a gallon. Yes, we know that, globally, that’s still cheap.
Just for the record, a local store has offered triple-discount on coupons lately (with certain conditions, of course).
I work in the service center of a supermarket chain in Illinois, though not one which has been mentioned here. We double the value of coupons which are less than $0.41, redeeming them for up to the cost of a single item. On store audit reports, the value of the doubled coupons is listed apart from the coupons themselves, as negative sales to the grocery department. On a busy day this amount generally does not exceed $15.00.
Perhaps not surprisingly, there aren’t too many coupons with a value of less than $0.41.