Crossword puzzle clue "to show by a sign"

Good sign or bad sign

Warning sign at a train station's food court? (NOTE: The original sign, without my additions, actually exists. It's in Grand Central Terminal in NYC, on the lower level — the food court level. The sig

Sign of danger — sign of socialism

Pre-sign sign

To show by a sign

Sign outside a hit show

Many a "Today" show sign

Sign up talk-show host at town dump?