The fare card system they implemented here tracks everywhere you go on their system. If you use the tickets you pay more, if you don't register your card, good luck when something goes wrong with it(and it will).

Your options are, travel anonymously, and pay more or risk losing the money on your fare card due to them just deciding not work anymore, loss etc. I've gone through 4 now in about three years. Two just stopped working and i lost two. They also don't give your $6 deposit back, so i've now spent an extra $24 i'll never get back, for nothing on top of the money i lost on the first two cards. I've registered them since.

Or

Get tracked constantly any and everywhere you go on transit.