I am troubled that the US justice system seems devoid of a basic understanding of modern technology.
These cards don't in any reasonable sense identify a person's whereabouts. They are cloneable, easily used by anyone. They are in no way tied to a particular person.
You missed a big point. It's not that it's perfect proof, court cases never have that. It's evidence, that's all. When you put that together with other information it all adds up to a picture.
In the computer world you are used to perfect security or it's useless. It's not like that in most fields though.
Buddy cashes check, photograph taken, Jones visible in background of photo.
Subway to girlfriend.
So everything fits. The truly scary part of the story:
During the interrogation, he said, it occurred to him that he had used his MetroCard on the bus and the subway, and he asked the police to check it. A detective took the card briefly, and then gave it back to him, and there was no further discussion about the card, he said.
have you read the article? it gives an example of a murderer who tried to fool metrocard ... but failed
the metrocard itself cannot be used to identify a person's whereabout; however, it can be used to constrain the movement
the key word in that article is "physically" ... the metrocard data is used to determine how physically plausible an action is
for example, one uses metrocard at 9amET in new york, then someone get killed in LA at 10amET, s/he can't be physically possible candidate even if ALL govt witness say so
of course, orthogonal info help too, a phone call at 930amET or even 705amET ATM withdrawal (with pic)
Kind off gives me an idea to make a special card that one can carry that is somehow linked to your identity and records all your whereabouts in a way that can't be faked.
Then if you ever have to prove that you were in a certain place you can give the card. Obviously it would make it pretty hard if you were lying so no one would want to carry it :)
(ignoring the various technology restrictions of this scheme)
I do this too, but for different reasons. It just seems like interesting personal data I could analyze some day. Does anyone know a practical way to grab this data electronically for analysis? I have shoeboxes full of receipts... I could tell where, when, and what I bought for the past 10 years. Merge that with photographs and emails and I've got a heck of a personal journal... problem is, i can't figure out how to enter the data short of hiring someone.
These cards don't in any reasonable sense identify a person's whereabouts. They are cloneable, easily used by anyone. They are in no way tied to a particular person.