Helped by the fact that we'd long since discovered an unmarked side door to our wing of the building was a convenient shortcut to the conference center, we made no wrong turns and went straight out through the hotel's loading dock exit and into the parking lot. We passed one fellow standing there shivering in only a pair of boxer shorts -- he'd aparently evacuated even a bit more precipitously than we had. Following good practice (I've been in this situation before), we moved away from the building so that any arriving fire equipment wouldn't have to dodge us.
Fairly soon thereafter -- less than five minutes, I would say -- hotel security advised us that there was no fire and that "someone had pulled a fire alarm for kicks and run off," according to what spread through the crowd of groggy hotel guests and overnight staff. As we made our way back upstairs to our room, I heard one woman, presumably one of the non-convention-member hotel guests, complain to her companion, "I told you they were a bunch of freaks!" which didn't make me feel too happy, but I wasn't going to stop and argue the point with her.
One thing about the design of this hotel on which both Lisa and I commented when we got here is that it's can be (and in our personal case is) a long way to a fire exit. There were at least two fire doors separting our section from the nearest stairwell. Based on my other modern hotel experiences, I would have expected there to be at least one more stairwell in this building.
I didn't get a lot of sleep this last night, and this alarm didn't help matters. Unlike yesterday, I do have a morning panel -- today, my first panel ("Awards: Too Many, or Not Enough?") is at 10 AM, so now I have to get a move on.
Update, 5:35 PM: the afternoon newsletter reports "Hotel surveillance caught on video the miscreant who set off the fire alarm." On the other hand, a different rumor suggests that someone set off the fire alarm as a way to finally put a halt to the Biohazard party, who were apparently still going strong (and very loud) at 6 AM.