If the DHS and TSA where done away with, do you really think airport security would change drastically? It could even get more insane. But at least an airline could offer less security, and those who want to fly with less restrictions would have the option, and the market would decide.
I can't imagine an airline ever allowing private citizens to carry on board the way LEOs can. (after only a 4 hour course, how highly trained!)
The same goes for other private events, and locations with tight security.
Remember, the bill of rights doesn't grant anything, only recognizes, and restricts the government, not the private sector.