Well this answers a lot of the questions I had about how the cards work, but not in a good way. Streetsblog San Francisco -- Clipper Card’s Dirty Little Secret (Hint: It Can “Go Negative”)
Here’s how the scam works, and mind you it is especially effective on BART, where you don’t have fare inspectors or conductors to check your Clipper card and catch you. At any retailer or vending machine that sells Clipper, load the minimum $2 dollars on a new Clipper card. Buy a bunch of them this way, if you like. Pay cash and do it at a Muni Metro vending machine in downtown San Francisco if you really don’t want to be traceable. Then ride BART where ever you desire and you will never have to pay more than $2. Let’s take Civic Center to the San Francisco Airport, a trip I made over the weekend to see if the scam worked as a Streetsblog tipster had suggested. I bought two $2 cards at the vending machine, paying $4 in cash. When I tagged into the system at the fare gate, the card had a $2 value. I rode to SFO, a trip that should have cost me $8.10. When I tagged out at the International Terminal fare gates, instead of an “Insufficient Fare” warning, which I would have seen had I been using a $2 traditional BART fare card, my Clipper card subtracted $6.10, leaving me with a balance of $3.90 of someone else’s money. After completing my return trip to Civic Center with my other $2 Clipper card, I ended up with $16.20 worth of BART rides for $4. If I had entered BART at one of the terminus stations, like Pittsburgh Bay Point, and traveled to SFO round-trip, I could have gamed BART for $21.80. Because the cards still register the negative balance, and I would have to pay that down before I could add a positive balance to the card upon re-loading it, the smart thing to do would be to throw away the cards. At a cost of $2 per card to manufacture, I’m essentially paying for the privilege of adding two pretty blue cards to the landfill. What a steal!