The 501st is always pretty solid about staffing events. And I appreciate their efforts. Security at a con can probably clear those guys pretty easily from the standpoint of screening volunteers since they've got manageable numbers of people who would volunteer with the 501st. I did also hear from some friends who were attending that Phoenix con, and they talked about waiting for HOURS to get through the security screenings that had to be hastily arranged following this issue. And in the case of screening a con where there could be thousands of attendees? That's a monumental task in comparison.
As for the lightsabers? I kind of get that. Not so much from the standpoint of people using them like weapons. It's not like fans with FX lightsabers are attending kendo classes to the point where they're dangerous with any kind of saber. Rather, I've come to find them a little distracting from a movie going experience since some people may be a little overzealous with lighting them. And I get the sense that they're not always prepared to think outside of themselves, and consider the viewing experience of other people in the theater. If you're in a tense moment of the film and you're super focused on what's happening on screen, having someone else in the audience light up an FX saber can be super distracting. So I'm a little more inclined to side with preserving the viewing experience for a theater full of people.
But back on topic? The DLT-19 looks awesome. And what armor are you going to be trooping in? Ever since (the first) Battlefront came out, a Scout Trooper using the DLT-19 (or similar long blaster) like a sniper rifle really struck me as an awesome look.