And that lesson is: ground staff at out stations are usually the least reliable source of information about ops. The elite phone lines, nwa.com or even flight-tracker websites like flightaware.com are all better. (A person could've logged onto flightaware, input the NW flight number of your incoming service, and learned that it was descending toward MHT while the agents there were rebooking everyone.)

If I've learned anything it's that counter and gate agents often say things authoritatively that turn out to be false, either to compensate for a lack of real data or to make pesky passengers go away: from "F has checked in full" to "We're not changing any seat assignments right now because the aircraft is out of balance" (this from a CO GA boarding a near-full 757!) to "That aircraft is still in Detroit waiting to be deiced, it may not even get here this evening." Sometimes it's not lying, exactly -- it's just not wanting to be seen as tentative.

Operate like a good journalist. Get everything from two sources.