Actually you just have to look at it from a practicality issue;
Any ban on flag burning will INCREASE the number burned.
Everyone that has seen an American flag burned in person in this country, raise your hand....
I'm guessing it's nobody. It's a solution in search of a problem. And the publicity of being among the first arrested for doing this under a constitutional amendment will be so tempting you'll see a massive explosion of people doing it.
And don't kid yourself there will be severe penalties; if a penalty is imposed that makes it worse to do this than beat your wife or drive drunk, etc., the negative publicity would be too great.
I have. In fact, I've had a hand in burning a few. Usually at the closing campfire of one of my Boy Scout Troop's campouts or summer camp session. Of course, everyone is usually standing there in silence and saluting, but we're still burning the flag.
a couple times. over a campfire, with all of us standing in silence. i was told this is the proper way to dispose of a flag that had spent its life being prodly displayed and had become worn and slightly tattered.