[HarleyLady27]

Then that explains yesterday, I noticed he had more security than normal, and it wouldn’t surprise me if he wasn’t wearing a vest...

[RoosterRedux]

Since people enter a venue in a line, security personnel visually vet ever person who enters the building. A problem person will stand out like a sore thumb.

And once an event starts, they have eyes all over.

Not to mention that the advance team will scour the venue inside and outside ahead of time.

Trump's security team is probably better than the Secret Service...the best that money can buy.