Flutterby™! : Clipper card trackable

The Bay Area's Clipper RFID transit payment card payment history, and therefore the user's transit movement, is subpoenaable:

“Absent a subpoena or a search warrant, we would not turn over any information,” Goodwin said.

Transit riders can remain anonymous if they pay for a Clipper card in cash and do not register it, he noted. People who don’t register stand to lose any money on their card if it is lost, stolen or stops working.

Careful out there, kids. And, yeah, it's really convenient to have my Clipper card debit my credit card when it runs out, but I'm wondering if I should go back to cash, just because.