It doesn't really matter to me though. I'm not going to work for a requester (no matter how good they pay) that blocks people that I know are decent workers. It's really not a matter of principle, it's that I don't want my account to be suspended because I made a mistake on a HIT. Not that I have a lot of blocks, I only have two total since being on mturk, but it's enough to make me nervous and cautious of requesters who do block. I will however work for requesters who reject for making mistakes.