How likely is it you'd be prosecuted for warning motorists of a speed trap?

CookingWithGas:

Only fowl and seafood, then?

This from personal experience:

If you piss off a cop, they can find “legal” ways to make you wish hadn’t. They can ticket you or arrest you on the flimsiest of charges and you will, at a minimum, suffer the inconvenience of a court appearance to have them dismissed. This may require the services of counsel, which do not come cheap. You can end up spending the night locked in jail even with no charges being filed. If you are driving at the time, your car may end up being towed. It will be expensive and inconvenient to get it back. They will bully and badger you and try to get you to take a swing at them…not sure what happens after that, as I am pretty good at controlling my temper.

In the U.K., a pensioner got done for wilfully obstructing the police doing just that in 2004.