THAT would suck soooooo bad. Execute it perfectly and wind up with a stone or twig or some trash eating your foot up the entire bike leg. Or having to stop to fix it!
That seems like a legit risk also.
I mean, I walk barefoot from the house to the car to get stuff out and it's concrete the whole way and I almost always pickup something on my feet in that 20 ish feet. Much less 50 yards or so of transition running.
The stuff stuck to the bottom of my feet is the other reason I don't do it. I can't stand having grass/rocks whatever stuck to my feet when I ride. I usally have a towel down in T1 that I can just steop on to before I toss my shoes on.
It's not perfectly clean but I had a 70.3 one time where somehow a fairly large piece of gravel got stuck to my foot. It dug a little hole in my arch the entire ride.