I also suspect that some miners may change the order of 2 and 3 depending on which pool mined the previous block.
No, not even-- they start mining the empty block without even receiving the block by spying on the stratum output of other miners.Quote
I think most of them learned their lesson, especially considering the value of each block currently.
That would be nice, but you can look at the published code to see it isn't so. 