They shouldn't say anything - there is nothing wrong with that unless there is some type of limit on a sale item as to how many you can get. The stores are reiumbursed the coupon value plus a handling fee so they actually make MORE money off of an item if a coupon is used on it.
Hardcore couponers use sales like this to stock up on items. I try to get as many as I can within the limits of the sale that my family will use before the item goes bad. I was able to get our favorite brand of yogurt for .25 a pack after coupon so I got several of the packs but we didn't eat it as fast as I had hoped and 1 package expired and had to be tossed out. It was a great buy at .25 but not a bargain if I didn't get to use it.
I usually order 10 to 20 of a coupon at a time for free items from a clipping service. I've got a nice supply of tuna, spaghetti, granola bars, instant potatoes, kool-aid, cereal, salad dressing and other staples with a nice long shelf life in the pantry right now. I get tons of free toiletries at CVS but those are limited per household as to how many you can get for each sale period.
You may also consider getting a few extra boxes of your freebies for the food pantry in town. DD's school has a food drive every fall and I load them up with freebies I got from couponing. They are always VERY appreciative.