It would be a good idea to read the article in today's Wall Street Journal online about a court case involving LE use of StingRay technology to locate, but not tap, specific cell phones without a warrant.  The article points out that this technology only works if the cell phone is powered on - the StingRay device works by mimicking a cell tower, catching the target cell phone's signal transmission from two locations, thus allowing LE to triangulate on the exact location of the target cell phone.  Minnesota LE is specifically mentioned as having this technology and they are quoted as saying no warrant is required to use it.

And I have no doubt that this tool won't be limited to organized crime or terrorism, but used to bust perfectly harmless but easier to catch hobbyists and providers.  I always use a hobby phone and it's off most all of the time, except when in use for the hobby.  I'm sure that's not foolproof either.  I can imagine a scenario where this is used to identify a room or hotel that a provider is staying in.  Sigh - what ever happened to the 4th Amendment?

The WSJ article

http://blogs.wsj.com/digits/2011/09/23/keeping-stingrays-secret-makes-case-tougher-for-prosecutors/?mod=WSJBlog&mod=

...since LE simply needs to pull numbers from ads and use StingRay to locate incalls. Surveillance would then be the next step I would think.

I would expect one would have to be involved in more infamous, & serious activities than sucking a few pacifiers from day to day for LE to take such an interest. That is after all a lot of time & money to be wasting on a simple misdemeanor. Mind your p&q's, keep a low profile, don't be a nuisance to your neighbors, & you should be fine.

No because it needs to be forwarded to an active phone line in order to work so they can still ping you.
Even then, Google doesn't mind sharing your info anyway.
Doing something like that to someone without a warrant is pretty much unconstitutional so that hacker has a good chance of getting lesser charges.

I agree, use of that equipment isn't really needed if they want a small fish.

Busting providers & johns is entertainment for LE, nothing else.  They know it does nothing to reduce prostitution (or trafficking).  They do it for their own enjoyment and for their enjoyment they are more than happy to roll out their favorite toys, Stingrays & portable cams (see today's front page) included.  If the equipment is just sitting around with nothing important to to, they'll take it out to play.

IMHO there are some serious constitutional issues about the use of this technology without having to get search warrants.  Again, we see LE all too willing to use modern technology to try and circumvent legal protections instead of using the technology in an ethical manners that respects the right of the citizens they are supposed to "protect and serve."