There's only one thing that could make me refuse powering up on steemit and that's the price of steem. If I have a significant amount of steem, let's say about 50000 steem, and the price of steem is at 10dollars, I would gladly sell everything and enjoy myself a bit.

Then when the price of steem goes down just like it always does, I'll swoop in and buy as much steem as I had before for a fraction of the price I'd sold it. That's one thing that could makee refuse powering up on steemit.

Another thing that could make me refuse powering up on steemit is if I have a pressing and urgent need for money and the value of steem is low so even if I power up, my upvote might not be much. I'd gladly turn down powering up and use the steem for other things.