It raises independence and drops the other stats, by a significant amount, but not, as Indirik says, enough to make the region revolt all by itself.
Chénier once did this to Athol Margos (Riombara, BT) three times within a week or two, and...I'm not sure if it barely revolted, or barely didn't. He might recall.
Can you do it without getting caught? Sure. But it ain't worth it, effects only become interesting if you invest a lot.
But as Anaris hinted, don't expect to make a 100/100/100/core region revolt just by spending a few hundred gold. I've used this tool on Athol Margos probably a dozen times so far, and it only had interesting effects at one occasion where it was already in bad shape. On the other hand, it does increase sympathy to your realm considerably, which is quite interesting if you want to FTO or CTO it.
Do it if the region has a large army or horde in it, or if it's starving (and only after the starvation effects started, not before), but otherwise don't bother. Also, do it by having in mind that you'll get caught, so if you have two characters on an island, always do it with the same, preferably the one with the least odds of getting captured.
