Might not be true, but I've also been told that wind blowing up the exhaust pipe can give false readings of a leaner condition. But regardless, a few points in idle afr's is not going to hurt anything.

 

my AFR is about 14 most of the time even when driving and at idle unless i hit boost then it goes to like 10.... but when i start my car cold with the GSC S2 Cams(retainers and springs) it goes rich real fast for about 30 seconds then lvls out. to 14. Before any real mods it would sit at 14-14.7ish

 

LOL, maybe if your in a tornado or something.