Good point, Ive seen others mention this as well.don't know how cold your mornings are, but when it's cold the fob doesn't communicate and needs to be warmed up.
The guys at the valet lot I use tell me it's common with all stop/start vehicle fobs once the weather gets cold (40* or less)
Fob sucks, I've had it loose communications while driving and get the "No fob detected" warning