first of all, I've found this board to be very informative.
Before I post my "stupid" idea, allow me to provide some information to my fellow Canadians who, like I, live in a province where detectors are illegal:
It's perfectly OK to bring in a detector from a trip to the US (I got back from a 7-day trip with an STi yesterday) and declare it. More likely than not, they'll want to search your bags, as was the case for me, but that's not a problem: customs do not apply provincial law, but federal law. They know you're probably going to break provincial law, but it's basically none of their business (in my case, the supervisor thought it was a pretty cool detector :-)
I admit I was a bit nervous yesterday, but everything turned out fine. Completed a hard-wired install today. I decided on left side of dash for quick removal and ran the wire through ventilation. Anyone with an E46 BMW, I'll be happy to explain.
Now, for the "stupid" part. I was thinking about building a small circuit with a timer and relay to disable the brake lights for 5ish seconds on an alert (probably with an override switch :-). This way, I won't be afraid to brake when I get a serious alert... Evidently, you'd want to be careful of anyone behind you. Crazy?