(A year later... can you tell I haven't been around here much lately?) - yeah, the side panels can fly off. I very nearly lost one due to a malfunctioning grommet. It seems World of Triumph can still sell some, which is a nice surprise (I haven't checked in a while). But yeah, after my scare I drilled a small hole through the longest, rear, support and threaded a ziptie loosely through the frame as well, and siliconed the grommets in thoroughly. So far so good. It's a simple mod I'd definitely do again.
The panels are £259 or something each when bought new, that's $330 and doesn't include shipping... expensive little mishap to lose one.