Does anyone actually use yarn-tainers? The plastic cylinder containers that you run the yarn through the hole in the lid? Do you like them?
My mother-in-law gave me one for my birthday. It looks okay in theory, but once you set it up with the yarn you cannot take it out of the yarn-tainer till you are at the end of the skein. So there is no latitude to be able to change ones mind about using it if you don't like it.
I use a ziploc bag that I can snip one of the corners out of, then I feed the yarn through there. If I decided I didn't want the yarn anymore, worst case scenario is that I would just tear the side out of the bag. It's economical and handy. I can't personally vouch for the yarntainers, but I'm glad you posted the inconvenience about them. What a shame--it's a great idea in theory.
I use mine all the time because I carry my projects with me always. I'm a fairly slow knitter as it seems I have to knit a row or two whenever I can, don't actually sit and knit much and these keep things neat and organized for me.
I also found something similar at my LYS, but vinyl so they're flexible instead of rigid. They also have some that hold 2 or 3 ballls so if you're using more than one color, you can keep them all together.
If you like the idea except for that one flaw, you could cut a hole in the middle of the lid of a plastic container, and cut a line from the hole to the outside for removing the ball when you want to. Like an ice-cream container?