How often does someone carrying out a planned crime carry a phone with them that is switched on, these days? Use of mobile phone data by the police has been standard practice since 2001, at least, and widely publicised.
Almost all of the time.
I read somewhere how the police once solved a crime by analysing a cigarette butt left behind in a stolen car, but within a few years it was quite common for them to find that a stolen car had its ashtray filled with cigarette butts apparently taken from a public ashtray: even joyriders were clever enough to thus outwit forensics. So it would seem weird to me if armed robbers or professional burglars were carrying switched on phones, and most crimes are committed by people who commit multiple crimes, as I understand it, people who have plenty of experience of how the police and the courts operate.
In online discussions there are always people who claim that criminals are idiots, but I don't think that's accurate. I reckon that when it comes to crime, most criminals are in effect a lot more intelligent than I am with my elite university degree and so on. But in general, the older I get, the more aware I become of my own limitations and the less likely I am to dismiss anyone else as an idiot.
Career criminals (mob, drug cartels, etc) yes.
But people who commit random premeditated crimes are more often than not (judging from trial) in "Fargo" movie territory, and most smaller criminals (e.g. gang members, methheads, etc) are dumber than cotton.
A lot of criminals (again, around here at least) are that stupid. The detectives have solved many cases just by searching for the suspects name on Facebook. Some examples were: seeing the stolen items right in their profile pic, drugs with the suspect standing there while holding a gun, a video of a friend recording someone breaking into a car, hell, they had to get CPS involved because a parent had a video of them hitting (it was hitting, not disciplining) their own child. All of that just on Facebook. The hardest they had to work to get those pictures was add them as a friend under a fake profile.
Now career criminals are a completely different beast. The law enforcement here (luckily) doesn't have many or any "advanced" criminals around here. There are definitely plenty of low hanging fruit here to keep law enforcement busy, and being in small town USA, once they know who you are, they KNOW who you are and who you hang out with.
The detectives always said that if most of these people left their phone at home, didn't take any pictures, and didn't tell their friends about what they did, that crime may not get much priority (or any) depending on what the crime was.
I don't have raw data to back that up, but it does happen here. I do agree with you about the career criminals though, but there are still A LOT of stupid people out there or maybe it's something in the water here.
>[2] Matching entry / exit point – we know specifically they look for that, so don’t match the last use and first use of phones, overlap it.
[1] https://www.youtube.com/watch?v=J1q4Ir2J8P8
[2] http://privacy-pc.com/articles/dont-fuck-it-up-6-opsec-with-...
All the time.