I've been roadtesting this product for a week or so now and, so far, I haven't had any complaints. There was the initial phase of getting used to wearing a quarter glove (hehehehe) but after that phase passed, I found myself sometimes forgetting to take it off (happens when I finish my classes and have to rush home to beat the rush hour).
How it works:
You slide your little pinkie through the quarter glove (I love saying that), adjust the seam so it won't be resting on the side of your finger (you don't have to but I discovered that my little finger gets strained a bit if I don't adjust the seam).
Then you just pick up a pencil, a charcoal, or whatever drawing tool you're going to use and start drawing! Simple as.
Verdict: Does it work? Most definitely.
Other Uses: Blending pastels on paper. Works best if you're using 2-3 colors on the entire area.
Now, I won't call this the downside, in fact it might actually work in favor of Jeannie (she owns SmudgeGuard, the company, and the concept). You'd get a lot of questions from people wondering what happened to your finger. If they experience smudging on the side of their hands when drawing or writing, they'd understand and even give you that "Why didn't I think of that before?" look. If they never experienced smudging (which is highly unlikely), they'd nod and smile politely (and think you're one of those weird artists 
).
Here's a photo of the SmudgeGuard taken from their website.
How to order: You can order one for just US9.99 through their website. You can pay using PayPal.
