I think it will be busy, but maybe not too busy! Do you have touring plans? I like to look at the dates on the years past. They historically rank the days 1 through 10. 10 being the busiest. Their historical numbers don't come out until the day has past, so they are pretty accurate (not the future predictions though because they have been way off lately) Historically, Labor Day hasn't been horrible. A 6 out of 10 last year and the weekend before was only a 5 even with the marathon. The few days after are 2s or 3s.
I think it's like the 4th of July. For so long, everyone thought "it's going to be crazy" so they just don't go and it ends up being a pretty decent non crazy day!