I had heard this, as well. However, in San Francisco, I get this icon in at least two different locations. The first is near the intersection of Bush and Presidio and the second is near the intersection of Geary and Park Presidio.

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David

Macan Turbo / 997.1TT (gone) / e83 (gone)/ e46 M3 / e90 335xi (gone)/ Sienna XLE Ltd
B7 A4 2.0T CVT (gone) / Pilot EXL-RES (gone)