Has anyone noticed that the rocker switches used on some of the sanding tools are very hard to turn on/off? Not a big deal really, but sometimes annoying.
I've had this problem with some DTS/RTS/ETS125 models. Up to the point where it was almost impossible to use the switch. When posting a question like this it would be nice to mention the extact type of sander(s) you're talking about. There's a good dosen of different types of Festool sanders, all with their own types of switches.
Knowing most Festool sanders and their specific switches, I assume you're talking about the DTS/RTS/ETS125. If that assumption is correct, then I know what causes it and how to remedy it. See picture below.

As you can see in the picture, the green switch of these sanders 'rocks' around a center column and has two prongs on the end with a nub on them that locks onto another pin, one on each side of the switch. The problem is that these two pins can become rusty and that gives extra friction which causes the problem. All you have to do is remove the rust. I use a Dremel with a small metal wire brush and that does the trick. After that you just have to screw the lid back on the sander with the two screws. Easy as pie.