If you're using superwash merino, regular merino or silk/bamboo blends, you will have more of a problem with steeks. There are a bunch of techniques to deal with those cut edges, especially by sewing them and using twill tape to cover them.
That being said, knitting doesn't unravel horizontally. It unravels vertically. Its like when you get holes in your knit socks or whatever. Pull at the horizontally edge and see how much it unravels. Then pull at the vertical edge.