[misnome]

Certainly it depends on which one of many jurisdictions Uber operates in.

For a start, in the U.K. it's illegal to use radar detectors [Edit: this first is apparently false; they publically stated that they were going to, but never changed the law. Other countries apparently do ban them, according to wikipedia.], and people have been given criminal convictions for "Flashing their lights" in order to warn incoming motorists of a speed trap.

[DanBC]

Is it illegal to use either radar detectors or gps camera locators in England? What law is it?

I'd be interested in a link to the "flashing lights" case too.

[misnome]

Apologies - apparently I'm mistaken with the first - apparently several years ago there were public discussions about it and they claimed they were going to, but never followed through. Probably some more secondary sources confirmed it for me that I never double checked. (Also, wikipedia claims that although the UK doesn't ban, plenty of other countries do - and in the US it seems only Virginia explicitly bans them)

RE: Headlight flashing, I can only find sources from a few years ago - http://www.bbc.co.uk/news/uk-england-humber-12823922 was the one I remember hearing about, but several other instances seem to have taken place; i.e. http://www.telegraph.co.uk/news/uknews/law-and-order/9324722...