I would never try to put an incorrect size tire on a rim. I know of two stories, One my Dad witnessed and the other was a friend of mine from when I was in the auto parts business.
The one my Dad witnessed, was back in the 70's, at at service station (remember those) A Shell as a matter of fact. A friend of his was using the tire machine and was r-n-r a tire. He had removed the old tire, and was placing the "new" tire (I am not sure it was a sticker tire, or just a different tire, but I would say was the proper tire for the rim). Upon re-inflation, the tire failed, and hit my Dad's buddy across the chest and threw him through the large glass bay door. He lived, but did suffer injuries.
Another one was a friend of mine at a different Shell station, he was installing a new tire. Had the new tire on the one the rim and was inflating it, while it was still on the tire machine. He had removed the large threaded lock "nut" from the tire and rim, it was just laying there, only being held down by gravity. The back side bead let go, and the tire launched off the machine, hit him in the head on the way up, went through the bay door (door was open, so it was up along the ceiling) through the ceiling and came to rest in the attic. He was rushed to the hospital with head injuries, and now has vision loss in one eye. He was told it the tire had hit him a bit more the the right (toward the center of his head) it would have broken his neck, or taken his head off.
After hearing both of these, I give tires a great deal of respect.... as they can and will kill you. I know it is an "normal" action, but I cringe every time I see someone set a bead with starting fluid and a flame......