Last time I went to the dealer for service they did two recalls and one of them was for something in the wipers. I don't know exactly what they did though.

 

Since I just bought my 08 IS-F I brought it to Lexus for a maintenence history. They said I had two open recalls. The wiper nut and inside trunk release handle. They did both in under 15 minutes and the trunk came with a free tank of gas for the trouble. They also gave me all dealer performed work. The service writer was really cool about letting me know all the history

 

I recommend getting this fixed or at least checking and tightening the bolt well. I got the recall notice but didn't pay it much mind. Then yesterday I needed to turn them on high during a rainstorm. This happened after about 30 seconds!

The two blades hit each other so hard that it bent the driver's arm bad and they have to replace it. They didn't even want to let me have the car back until the part came in due to the safety hazard. However, I need to clean her up for the Mega-Meet next weekend

 

I had mine done when I went for an oil change.