Here's what I've found out about the cause of the the sticking pedal.
The slave is a concentric style. It has a plastic sleeve that, when the clutch gets hot, melts around the shaft. That's what's sticking. You can free it up for the first couple of times but it gets worse and worse as it melts further, eventually so much so that it's out of round.
Ergo, riding the clutch causes excesses heat to transfer and is one of the roots of the problem.
That said, I don't ride the clutch, but I used to sit at the light "ready to go" when the light changed to "surprise" people off the line. I've had to replace it twice (not counting the bad one from the factory) but I've since learned not to do that.