This is a bit of a dumb argument to me. I think the Jedi, in all their teaching on the Sith, would obviously learn of the rule of two--they are obviously aware of it, as the only way that the audience is even informed of it is when Yoda talks of it. So obviously Anakin would have known of it.

The real question is: how the fuck do the jedi know of it?? The sith have been hiding for a millenia using this very technique--but then out of the blue Yoda knows about it. What the?? Sloppy writing! This is where the real story flaw lies and the answer is simply that its a plot hole.

The previous debate is merely a by-product of OT versus PT/Saga--ESB was not designed with any rule of two in mind, but with the retroactive changes made by the PT revelation of a "rule of two" existing, ESB can be re-evaluated with this interpretation in mind, if so desired.