Passed through DIA security this morning on my way to O'Hare. As soon as my gear went through, they immediately called for a supervisor.
Overall, it was the standard scenario where they swab it and look for residue.
Afre running it through again, the big concern was a device in the center of the rig that looks like a torch of some sort. They wanted me to open it and show them.
I pulled out the iPad and showed them the documents and description of the Vigil2, they were looking at the Control unit specifically. http://www.vigil.aero/files/1997.pdf
Over all, they were actually pretty casual about it, not rude by any means. They even used it as a training opportunity for the other agents on hand.
Like you said, kowalski, how you respond to them likely drives their reaction.