Good question, I use foil on the probe becasue I kept killing them without the foil and the foil lets me set the lid down on top of the wire without hurting it.
Also I want to add I normaly wont use the prob until I feel there is less than 20 mins or so left in the cook.
I have cooked so much with my SRG's a can guess very close to IT. Not that I'm bragging but I have used the H#ll out of my units