There is no need to temporary ban such items, and if there was a problem with them in first place, there would be ban on them every where. Not just for this convention.
The role of the thought police is ever increasing.
What you have demonstrated is a total failure to display the ability to comprehend the basic purpose of government, civil justice, and laws, as it pertains to the USA.
You can openly display your contempt for our society, and not be arrested for your opinion.
I can also openly display my contempt for you, and not be arrested for it either...unless I threaten you physically.
What you and your followers always fail to grasp is one simple fact of human nature, life, society, law and government.
That pertinent fact is:
Civilization is a wafer thin veneer controlling human nature.
Courting anarchy is only fun in theory...