At the end of the day... how much money is coming out of our pockets to deice the jet. Is it really worth the distraction of safety of operation if you even have the least doubt as to whether or not to deice? Do you think the bean counters upstairs really take notice on who deices and who does not?
One could say, although I don't care for the description, is that SOPs are designed to protect us, our crews, passengers, and aircraft from ourselves from going into business for ourselves.
SOPs instill disciplines required to maintain a safe operation from report of duty to end of duty... which such details are covered in the non-normal section of the FCOM.
To one and all... be safe out there during this winter flying season.