You don't have your location enabled, that would give a better answer, Canadian artic circle would be different from mexican desert...
people have discussed it on Hybridz before, consenus seems to be that if you're in a effing hot location such as Texas or Hell, they're usefull, but anywhere with a normal climate it's fine to haul it off. it's a matter of how hot the underbonnet temps get, if the car can cool in the ambient temps, everything is fine, if it's too hot and/or sunny where you are and the car can't loose the heat, heat soaking of the fuel rail may occur. unusual, but it does sometimes happen.
so, are you somewhere hot or up in the chilly mountains?