Quote from: rigrenter on September 24, 2015, 06:35:14 AM

If I may ask: what exactly is the point of withholding blocks? The one and only valid reason is simply to be evil. Because by withholding blocks you don't gain anything, you can't just use the block that you've withhold-ed. So I agree while this is theoretically possible I believe there are aren't any miners who would care to just spoof around, spend time on configuring and executing withholding and gaining nothing from it. As a matter of fact it's actually a bad thing for miners to do this since on the long term they would hurt rental services and would't be able to get the extra money that they are receiving by selling/leasing hashing power/rigs for higher price compared to direct mining. So, in my opinion this is a non-issue at all.

One and only? Hmm ... I guess you've not thought too much about it ...

Well ... if some pool wanted to destroy some of their smaller competition ...
It's quite common for people to hop off one pool onto another one when luck is bad but well within expectation.
Withholding on a non PPS pool will of course make the pool's luck seem worse.

Also there's the simple concept that people will rent hash due to wanting to gamble on that.
Renting hash will of course cost more than the expected BTC you will get, so renting is simply gambling.
Some gamblers can often be influenced by failure, to give it ... just one more try ... to get back their losses.
So if they aren't getting blocks (or getting fewer than expected) then they may well want to rent more ...

A couple of hours ago the data-centre where my main pool server is, was under a major DDoS attack.
It wasn't directed at my pool, but at the large data-centre.
Yep people may do such things simply because they want to and can do them.
That's how it is in the real world ...