

How Retail Stores Track You Using Your Smartphone - denzil_correa
http://lifehacker.com/827512308

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gnicholas
The article suggests "turning off wifi" so that stores can't track you. Is it
really necessary to turn it off entirely, as opposed to just setting your
devices not to join networks automatically? I'd think that the latter—which is
the normal setting for many people—would be enough, although I could imagine
that there would be a way to track even devices that are not connected.
Fingers crossed that stores aren't getting that sophisticated.

~~~
mmagin
To save on battery, portable devices tend to actively probe for networks (i.e.
it is cheaper to transmit a packet than to leave the receiver on for long
enough to hear beacon frames from the access points).

Thus, even if your iThing doesn't automatically join the networks out there in
a store, it is still emitting packets which contain its MAC address.

~~~
dwild
Really? Why do they need to emit anything? They could simply listen...

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Phargo
How real is this and how accurate can it be?

Pure conjecture here, but if retailers are getting in on this jig is it safe
to assume that local, state, or federal governments are doing this with public
wifi ports? If I walk into a courthouse and my phone is searching for wifi am
I tagged as being in the building? Would it be possible for government
agencies at any level to subpoena this sort of information from retailers?

~~~
diydsp
The newly-built, PV-covered stop&shop on the way home from my work has a flat,
black board with the name "Motorola" on it hanging over the entrance.
Presumably, it's full of antennas. Since Google acquired Motorola, I'm sure
this data is being resold and who knows what kinds of restrictions there are.

It is unknown what signals it records. It would be nice if someone who knows
cell phone signalling can chime in on how much is legible in this way.

As far as legal records, well, everyone on HN probably knows how easy it is to
fake a WiFi MAC address and make it seem like someone was at the scene of a
crime, or seem to be innocently hanging out somewhere else. So subpoena'ing
this information might not lead to useful evidence, but probably to lots of
confusion and prosecutorial mistakes and disasters. I would love to know how
easy it is to fake a cell phone IMEI or other identifying info.

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shizzy0
WiFi is no good outside one's house anyway. Every store/public-place sets up
their WiFi to require you to agree to a terms of service, which is an
annoyance. Best to just turn it off anyway; 3/4G always works. Why bother with
intermittent WiFi that some companies are still trying to charge you for?

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sciurus
Discussion of the NY Times story:
[https://news.ycombinator.com/item?id=6043183](https://news.ycombinator.com/item?id=6043183)

