First be positive it is rust it is kinda late in the season for rust but it possible. If there is a reddish orange dust comming off onto your shoes then it is if not the turf just maybe beginning to go dormant. If is rust apply a high nitrogen fert. with no SCU such as 32-3-10.
I've seen some rust around here lately (NJ like Anthony) even though its kind of late for it. However, we are in a drought, we've had heavy dews and temps have been well above normal, so conditions are right for it to happen here I guess.
If you check those same blades earier in the day while there is still dew, it will rub right off like Rodney is describing. Later in the day when everything has dried up, the rust seems to dry up also, so it doesn't rub off as easy.
I have rust on my personal yard right now. Showed up about a week ago after it was real warm, rained for a couple days, then every morning real heavy amounts of dew for about a week. Real cool at night warm during the day. I have never had rust show on my lawn before. Conditions just right for it, I guess.
I even have it on 20 rolls of sod I put down last month where I took out a tree for my driveway expansion.
I have it at two accounts that I have never seen rust on in the five years I have done them both.
I do not know if the fall fert I just did will kick it all out or not? Hope so!