i dont think it would hurt anything either. your Glow plugs stay on for 1-2 minutes after the engine started anyway, and if the engine is still hot and kicks right on, then that means your glow plugs will stay on 3 seconds longer. i do it all the time if i am running errands and keep turning my car on. if the engine is hot, even after 2 hours, it kicks on after 1 second glow.

__________________

Grey '91 350SDL 214k Dad's car FOR SALE!!
Beige '81 240D 4 Speed 254k SOLD
Blue '82 300D 225k SOLD
White '95 E300D 46k SOLD
Blue '87 190D 2.5 Turbo 315k SOLD
Brown '80 240D 4 Speed 716k SOLD
Beige '80 300D N/A 119k SOLD
Blue '85 300D Model 186k T-Boned