Crying Wolf?

When I find myself heading to Bloomington my route almost always takes me past the Minneapolis-St Paul Airport. Since 2002 I have been greeted with these messages on a flashing electronic sign:

Suspicious Activity? Call 9-1-1
Threat Level: Orange

I've often wondered if a sign asking me to call and report suspicious activity was itself a suspicious activity. In a sort of Orwellian way. But thing that gets me is that I don't remember the threat level ever being anything but orange. So either they don't know and want everyone to expect the worst or they do know but they don't want us to know. I just wonder what it would be like if the National Weather Service took the same approach.

In Minnesota we can get severe thunderstorms and/or tornadoes from Mid-May to Mid September. Imagine if they decided that every year on June 1st they would issue a Severe Weather Watch for all of Minnesota. It would stay in effect until August 31st no matter what the actual weather and threat was. For the Winter we would run from November 1st to March 31st with a standing winter weather warning. After all we've gotten lots of snow in early November and March used to be our snowiest month.

If NOAA did that people would never know when to be really concerned about a weather event. Isn't it the same with terror threats? If we don't have a specific threat should the level be Blue, A general risk of terror attacks? But what do I know? Only what they tell me.