Although I believe your experience with what you shared to be somewhat isolated incidents I don't believe this happens often. One area I fish when I've only a short time to fish, I've caught hundreds and hundreds of bass from over the years. Although not every bass I catch here touches the ground, but a good amount of them do. I rarely see a dead bass from here. I can't even remember the last time I saw a dead one from there. Now if people are going to attribute other variables along with what kills the fish, covered in dirt, out of the water too long, breaking there jaws, bounced of concrete walls or rocks, then I agree wholly that all are contributors to it's demise. Just laying it on the grass for a few seconds more times than not will not kill a bass. Is it potentially hazardous, sure, is it certain death, no, not even close.