i remember reading an article that explained why mainly environmentalists don't want cars to idle when cold and they had good evidence to support their case. it appears when you idle, the cat converter takes longer to warm up and the cat converter only works when its above a certain temp; so when its cold all those harmful emissions are being passed through. then the group asked a few execs at domestic car companies their thoughts and basically the execs said that newer vehicles arent really meant to be idled anymore for long periods of time, because they know 1) people wouldnt like to have to follow a warm up procedure and 2) becuase its better for the environment if you drive slowly, helping warm the cat converter. one exec at chrysler even said something like 30 seconds max, just to be certain proper flow of the vital fluids. some cars out there even have different features to help protect/help the car when its cold like the 1st gen scion xA and xB would not shift into o/d until the engine reached its operating temp range, a few more have since followed this idea.
bottom line: it sounds like unless your owners manual outlines a specific warm-up procedure, you can just drive away after a few seconds if you so please