Any kind of touch typing? No, I don't agree with that. I can type 140+ wpm and don't look at the keyboard, and I can hold down shift while typing CONSTANT_NAME. Pinky on shift, remaining 9 fingers type CONSTANT_NAME. The pinky would not be involved with this particular constant even if it were free. The kind of touch typing you learned in school has a problem with this, maybe.
A is normally typed using the left pinky, so holding left shift will force you to use the left ring finger for it.
To be fair, on some keyboards, including the one I use, it's easy to reach both the right and left shift keys, so it's easy to alternate shift keys as needed to avoid using other fingers or moving your hand from the home row.
I guess it's important to note that I would use the right shift for this. I have the ability to choose on-the-fly rather than be forced into one or the other by a typing method that I learned in school. I could still do it with the left shift but it's not the one I would choose for this.
It's probably fairly obvious what I think about the taught-at-school touch typing method. It's a decent middle-of-the-road option that's intended to be easy to teach and to work for most people in most situations; that's all.
