Did my lil test today using Torque Pro:
Idling @ red light with D or S engaged alike, yields ~1% less RPM than @ N:
Something in the tune of 760 RPM w/ N and 752~757 RPM when in gear...
Yeah, 1% of an idling engine's torque over a year's regular driving is probably wearing the average clutch pack as much as what? 1/3 of a hard launch?
I'd like to see what the clamping force is when he's actually driving. Or just taking his foot off the brake in drive. My guess is more than 2.4 bar at idle. A slightly slipping clutch at idle is probably better than a slightly slipping clutch at wot. Just a guess. I think it's a very miniscule amount of wear and won't burn or glaze your clutch packs.