Wow, TIL that you need to prepare beans in a specific way.
Yup, I had no idea either, and have several times cooked beans slow and low in a crock pot. Guess I got lucky. Won't be doing that again.
If your crockpot gets hot enough to boil, the beans will be fine.
Ah, this is why - we normally have bubbling in our crock pot (which is close enough to boiling it must count).
The bubbles are the definition of boiling: enough water is being heated up to transition out of its liquid state and into a gas to cause a bubble to form, and rise to the surface, and escape. A rolling boil is when the whole liquid gets into a pattern of rising to the surface and then being pushed out of the way by the heated water coming up from beneath. If what you're seeing is tiny bubbles rising independently to the surface, what you have is a simmer. A simmer is definitely a kind of boiling but it does differ from the rolling boil and is a lower temperature that cooks more slowly.
For most recipes that aren't candy, a simmer is sufficient. It's definitely how people cook beans and rice although the preferred way is to boil the water and then reduce the boil to a simmer. (Rice cookers cook by simmering and do not appear to achieve a rolling boil at all.)
At higher altitudes water reaches the boiling point at a lower temperature because of the higher air pressure, so people adjust by cooking their jams, jellies and other rolling-boil foods a little bit longer. (Incidentally, the temperature can become much higher for foods that aren't water-- a roux is called "Cajun napalm" for a reason and a burn from half a teaspoon of boiling sugar can be serious whereas the same amount of boiling water is mildly annoying at worst).
In the specific case of a crockpot, the kind that will boil your beans (if left on long enough at the high setting) generally has a smaller top surface area (where heat is lost), effective insulating walls (to keep heat in), and a larger and more efficient heating element on the bottom. The crockpot also has to be left on long enough to reach that boiling point. Of my two crockpots, the smaller one can achieve a nice rolling boil even when full, because the physics are right. The larger one can simmer, but it seldom breaks into a full boil even if left on overnight.
/kitchen-physics