It can happen - in a bit of a "You scratch my back, I'll scratch yours" way. There was an advert by the ITC a few years ago where they mocked up an Australian Soap Opera. One of the characters placed a beer can right in view of the camera, obstructing the viewers' view of the action... This was mainly to point out that they were trying to stamp out product-placement in TV shows. So actually it's quite unrelated, but I'm not going to delete it because I'm stubborn.
So back to the original question, then. Yes, they can and do, but not often, and I can't think of any examples. More often than not, though, in cases like your example of a supermarket, the products on the shelves will be non-descript generic products. Unless the advertiser is a big brand that makes lots of things... so maybe if Kellogg's is advertising Crunchy Nut Cornflakes and has a shot of someone buying them in the Supermarket, you might see other Kellogg's cereals and breakfast bars etc. next to the Crunchy Nut Cornflakes. Sometimes the brands are so big that you might see washing-up liquid next to catfood.