Well, I spoke too soon...
I spent that rally weekend with a bucking and snorting bitch of a scoot. She would not idle at any light or stop sigh, I resigned myself to letting it stall or shutting it off and flintstoning it or just re-starting.
After that weekend (photos below) I was not able to ride for a few weeks and then I tried a new air filter, sea-foam, more idle adjustments, prayer, divine intervention, and profanity and none of them worked..so I took it to a professional.
He and I chatted for a bit when I got to the shop and he was confused... and bewildered... and impressed. I have nearly 32,000 km on her.
He called today, she's fixed and ready to go. It took him 30 minutes to determine that it was a vacuum hose that was cracked.... I think this may go all the way back to my stall in the rain.