Generally tripods are not just for crowd safety.

And I'm sorry I don't know but was a bit surprised (suppose I shouldn't have been) that everyone had to give up their umbrellas before going inside for the Seattle rally.

Guess if I had to stand out in the rain and then give up my protection, I would take the worst of my umbrellas or a tarp.

The standard disclaimer is always attached to events on Bernie's site:

"For security reasons, please do not bring bags and limit what you bring to small, personal items like keys and cell phones. Weapons, sharp objects, chairs, and signs or banners on sticks will not be allowed through security."

Maybe contact the campaign?

Info@BernieSanders.com or 855-4-Bernie

I believe I have seen people besides the press with DSLR's, but best to call.

I am an avid photographer (almost entirely landscape and birds/wildlife). I emailed the campaign and asked that question before an event in Greenville, SC that I was going to attend. It took a day or two but they emailed back that I could, but it would have to go through the security screen with everything else. I went to the rally but decided not to take my camera.

The screening is like what you go through in an airport. You can send your camera and lens/lenses around the x-ray screener and have them checked by the security people.