This morning’s Examiner reports that the city failed to give fair warning to 20,000 motorists fined $100 each for mashing cell phones to their ears while driving.

The city did a poor job informing the drivers (many who come from the suburbs where the action is only bad form) that it’s banned in the District, the paper learned from a Police Complaints Board report released Thursday.

Well “boo f’in hoo,” as my colleague might put it.

Ignorance of a law is generally not a valid excuse for breaking it, the Examiner reporter writes in the second paragraph, and he is correct.

And law aside, only a driver from some Virginia dark holler (where even Verizon reception is spotty) could have missed the notion that driving one handed with a phone in your ear is felony bad judgment.

Perhaps at District borders we should install signs as Virginia does to advertise its radar detector law.

“Welcome to the District of Columbia,” the signs would read. “Leave your guns at home. If you’re going to smoke, step outside the bar. If you chat while driving, buy the dorky earpiece. Consider yourself warned.”