There will be plants and impostors around to make us all look like a bunch of d!(k$.
Whoever organizes this needs to put the word out... everyone be cool and keep an eye out for those who aren't, because they WILL be there - conveniently in front of the CNNABNNBCCBS cameras.
Bring along a can of that bright orange spray paint that they mark underground lines with...
and “tag” the plants.
You have identified a very serious security issue. Not only will the leftist gun control idiots be there, but they will have plants who are carrying illegally consealed weapons and concealed long guns, so they can pull them out in front of the cameras to defame every legitimate gun owner in America.
This aspect needs to be addressed early on, and legit marchers need to be organized into cadres wwhere everybody keeps an eye out for a stranger with a gun.