The reason's previously mentioned.
The worst IMO, because it's the hardest to fix, is wear to the engine's
trust bearing.
Then you have wear to the throwout bearing and possible bleed-off of the
seals in the clutch master and slave cylinders.

The thrust bearing is a sliding bearing, not a roller, and is entirely
dependant on oil film for lubrication.
I wouldn't want to put enough force on those bearings to disengage a clutch
cover at 1000rpm's for 5 minutes strait.

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
levi hawkins
Sent: Wednesday, July 22, 2009 5:22 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: was: Friction, any extra wear 'n tear?

This happens to bring up something I've been wondering about.
I recently was required by the state of Nevada to take a driving test with
one of their inspectors.
At the end of the test I had passed, but he mentioned what I had "done
wrong" during the test: Sitting at a red light with the gear box in neutral
and my foot on the brake.
He said the state wants us to be in gear with the clutch pedal depressed.
Of course I'm not going to change, but my first thought is, wouldn't this
cause extra wear on components? Some of these lights would have you sitting
there for 5 minutes with the clutch in.
I really don't know, but I'm curious if anyone does.