A few years ago, my black lab sniffed a case just ejected from my AR15. He burnt his nose and now avoids these spent cases like the plague. Thankfully, he did not get a fear of guns and still loves to hunt. I've since purchased a strap-on net-type catcher for my AR, much like the one Midway has on sale now for $7.99, part number 855937. It works great.
For catching brass coming out of my 1911, I have a cloth bag type catcher that that slips on your shooting hand. It catches about 75% of the cases and is not too cumbersome once you get used to it.
Regards, Chappy