Here's an update. They politely told me to **** off and changed their tune as to why the warranty wasn't valid. It's because I'd dropped it. I'd (reluctantly) accept that answer if they said that the first time.
On the plus side, I did try on a few helmets (despite not wanting to buy another BiLT) because I had some free time, and wasn't impressed. Then I slipped on the
BiLT Techno (old model) and it fit my particular head like no other helmet has. It's a BiLT, it's only DOT rated (I heavily prefer ECE), but as Ninjette wisdom has taught me, having one that fits and conforms to your head nicely is one of the most important things for safety, so I went home, thought about it, and picked one up off the website. It's here and I'm thoroughly impressed. We'll see how she holds up over time, though.