It would seem at the very least that a president would be kept informed about these serious security issues revealed around the weeks and months of internet chatter regarding violence at an event he organized, even through a proxy, and would be the featured speaker.
My conclusion was that the administration knew the hundreds of people armed and dressed in tactical gear were not a threat to the president. They were his “stand by” gangs. His men and women ready to do his bidding. No surprises except the president’s reluctance to end it all immediately once the fighting began.