I think it would help your variance and be a better move in the risk aversion department to surrender more often when in doubt. To make the wrong decision and not surrender should prove more harmful than to surrender when it is not called for I would think off the top of my head.
We always surrender when we have neg EV so is it not smarter to err on the side that gives you half your money back?
Maybe not though because if you surrender exactly when it is a toss up to surrender or not, in theory, at those times you would win all your bet half the time if you made the right hit/stay call. It helps variance but not EV, right?
I know, get out the whip.