Why do many minifigures have printing on their neck pegs?
I also remember most (if not all) of the minifigures from the classic Space, Town, and Castle sets from the 1980s having similar printing on the neck peg. (I don't have a good sampling of current minifigures, but I've seen some with and some without the printing.)
What is the printing for? It is not visible when the head is attached, it does not seem to resemble anything (like a tie or scarf). The only thing I can think of is to prevent the head from sticking to the neck peg (or to reduce wear on the plastic itself), but if that's the case, why do some torsos have them and some don't, and why would they be only on the front of the neck peg?
(My guess for the last answer is that their manufacturing equipment usually prints only on the front of torso anyway.)