>Presumably the only reason they picked this strategy is that they know it is such an absolutely ridiculous step that nobody does it.

Oh absolutely.

But to play devil's advocate, your wifi device is basically an always broadcasting radio antenna that rarely moves or changes. And SSIDs are broadcast by design.

It's a digital landmark.

I bet there are a lot of other companies other than google using it too. And even if you used google's opt out, they're not going to care. So opting out is pretty pointless anyway. So while it feels invasive because we lack a sensory organ for radio, your router is constantly broadcasting (advertising?) itself as a part of normal operations. SSIDs aren't private information. It's more akin to an amateur radio callsign, except you can change it at will.

And since they're no consistent convention for naming your wifi there are probably 10,000 "FBI surveillance van"s. The only useful data to an outsider is location.

This was going to be utilized by someone, and probably already is by the NSA. So google doing it is no big surprise.

Again, devil's advocate here, but SSIDs are broadcast on purpose. Sacrificing security for convenience as always when people are involved.