You've heard too many scare stories. There is no need to put clumping bamboo in a pot...it's not going to go anywhere. In general, bamboo do ok in pots, but you have to be prepared to repot every so often as it grows. When planting bamboo in a pot, use one that flares out at the top. If the opening is smaller than the diameter of the pot at any point, you won't be able to get the bamboo out without smashing the pot because the roots will grow out to the sides. I sometimes keep bamboo in a pot for 1-2 years, but they always do better in the ground.

With our alkaline water in so cal it seems nigra hates pots but many others seem to do pretty good. Good enough to sneak out of the pot usually. If you have better water then even nigra may do well

I bought two cheap terra cotta unglazed clay pots and planted yellow bamboo in both. I then put the pots on either side of our entryway. This was in Portland, Oregon. In the summer they were shaded by a tall tree. They door faced north. They grew in those pots for 15 years, and when we sold the house to move we left the bamboo in the pots. Nice and healthy and tall they were - and their roots didn't grow out of the pots. All I did was water them - no fertilizer or anything.

I've also seen them growing in pots indoors in malls in Portland, and they grew just like mine.