Great discussion. Brings up some important issues.
One for Maxie. Having the art department start there for placement...especially for CTS allows the shop to streamline setup.
If screens are set up using film, then there should be a guide in the screen room to set things up in the same location all the time. But like ZaneGun said, sure, it should be what the customer wants.
I've been in some shops that had the art printing randomly in different spots for the same type of position (even when using cts). Never in the same height, up and down. (not using any templates) that made the output base don the art size... that caused the press operators to have to move pallets in and out for each job! Crazy. Position is important.
That said, the term "fingers" was/is still used loosely and a lot of people use that term knowing it's to be taken "loosely.
It's something people can refer to quickly at any time...rather than getting a ruler. Lets face it. even when you specifically say "4" down", every shirt does not get loaded and printed exactly at 4" down. Some dead on, some a tad higher, some a tad lower. Some a little to the left, some right. It's just that the target window is tighter. I guess that's why "fingers" is acceptable. Who's fingers? it's arbitrary. A fat finger or a skinny finger...it's "close enough" but, we all know this. I see your point. Fingers just sounds as if it's not that important. Like close your eyes and toss a dart and hope it gets close.