I would be more worried with all those clubs that they have lying about around the field.
More anti garbage ... post whatever signs they want it would have no legal effect.
Oddly enough, a player found the gun and turned it over to an ump .. nobody went crazy just upon the sight of a gun.
Seems like the facts don't support the concern.
And don't rifles have a range that is greater than the distance covered by a park?
Perhaps they should build an enclosed field. Or an underground one. Or build one in space.
Or not have baseball at all.