@croraf If heard around and I think this is maybe also this what some posts on bitcointalk mean.

We have underestimated defefending lines in majority attack scenario.

The double spending attack is so obvious, that that honest owners should just ignore it.

So double spending only creates a fork, the bad boys are interested in the longer new chain but the honest are still on the shorter (!!!) real chain.

This defense and others (like back-attack via a DDOS) are already discuted at some places like cryptocoinsnews.com/4-lines-defence-51-attack I'm not sure if defending lines really hold in attack case, but they exist and so risk for the attack is to high if he ignores them.

And there is still one problem independent from the concrete situation. If we want to do an attack profiting from decreasing value, we can leverage profits with leveraged shorts, but how do we leverage our defending lines.