Recently my wife and I attended a MLB game at Camden Yards in Baltimore, and experienced the light security measures in effect there. Not much, really; they inspected my backpack at the gate, probably looking for glass bottles, beer cans, etc. A bried inspection, almost apologetic, and a thank you followed. Later, we were walking around the perimeter of the park, and blundered into a chained off section that was reserved for a private (outdoor) party. The agent asked to see my ticket, and I explained we were just trying to make our way around to our seats behind home plate, and he courteously pointed out the route to bypass the party area.
The point is to contrast the way our government's TSA treats passengers at an airport to the way private security operates, as a general rule. When (not if, apparently) TSA starts random screening (including use of backscatter scanners) at ballgames, the first thing that will be lost is civility. Anyone who has experienced being barked at and ordered around by TSA at an airport will agree with me, I'm sure.
For the sake of our enjoyment of our national pastime, I hope that the league and the team owners will staunchly resist allowing TSA to inflict any kind of "security" on the public at the nation's stadia, minus a very specific threat that they are obliged to follow up on. Given the sports world's almost jingoistic pandering to the military, however, I have slim hopes. However, we noted that at Camden Yards, at least, management has finally dropped the playing of "God Bless America" in addition to the national anthem, so maybe the tide is changing to a more relaxed atmosphere. We'll see.