user93038: If you own 51% of the mining power and decide to ignore all blocks not mined by yourself.
You would eventually end up having the longest chain, and would eat up the 49% of block-reward you werent getting prior. 
And now control 100% of the blocks, and could censor transactions etc, since any blocks not mined by you would eventually be a stale fork.
Is there some measure that would stop this?
It seems if you control 51%, it would be in your economical interest to ignore blocks not mined by yourself. 
(other than it being bad publicity for btc, and maybe crash the price)

user12983: Yes. The owner of 51% can get 100%. This is attack-51 itself.

Is there some measure that would stop this?

no

93038: <p>If you own 51% of the mining power and decide to ignore all blocks not mined by yourself.<br>
You would eventually end up having the longest chain, and would eat up the 49% of block-reward you werent getting prior. 
And now control 100% of the blocks, and could censor transactions etc, since any blocks not mined by you would eventually be a stale fork.</p>

<p>Is there some measure that would stop this?<br>
It seems if you control 51%, it would be in your economical interest to ignore blocks not mined by yourself. 
(other than it being bad publicity for btc, and maybe crash the price)</p>
 12983: <p>Yes. The owner of 51% can get 100%. This is attack-51 itself.</p>

<blockquote>
  <p>Is there some measure that would stop this?</p>
</blockquote>

<p>no</p>
