Why do you think you would get double reward then? at the same time you would be just long one of both...
Because instead of 1 BTC on A and 1 BTC on B I would get 2 BTC on A/B.
You'd risk getting stuck with all your bitcoin on what turns out to be the fork that dies?
I'm not going to be on which (if it happens) fork wins, I'll play it safe and hold all chains until it's settled down.