I think this is just literal rickrolling.

sounds like it's on a major bus line which narrows it down pretty substantially

I'd suggest playing darude - sandstorm on loop, fairly loudly but with a (cone) directional speaker pointing straight upwards, spiraling in towards mission & 20th st starting ~6 blocks out in each direction. Record the time when you reach each intersection, and you'll know exactly which street segment you were on when your song got shazam'd, without having to actually ride on every segment (save roughly 50% travel time compared to doing the full grid).

Space-filling curve with a single song sequence? …Non-Euclidean space-filling curve, technically, because it has to fit the city grid topology.

Large phased-array speaker on a stationary balloon platform above the city, capable of rapidly scanning and blasting every telephone pole in the neighborhood?

If you’ve never lived in a major urban area in the US, I imagine this might seem strange. People drive around with music playing loud enough that a crappy mic would easily pick it up.

I'm wondering the same thing... Music loud enough to be recorded by a "crappy Android phone" placed "on a pole"?

Do you not live in SF or NY?

Living the meme

I appreciate your username in this context.

It was me - I will say that wardriving rickroll would be complete overkill