you used to able to lock in a low risk profit using the hedge facility a few years ago using the following strategy..Maybe.
Lets say we had data due out and it was going to move the market in a big way in one direction or the other -
You take a long position and immediately hedge it (ok you pay the spread but that's OK).. you could attach guaranteed stop losses as close as you were allowed to both positions .. - number comes out and the market jumps 50 points higher.. your short is stopped out for say 20 points.. but your 50 points higher on your long! ker ching... sadly I cant find a spread betting company where that is possible anymore ! bstards closed my account but was a fair cop I guess!
That was the only use of that feature that I ever figured out.. try explaining the hedge feature to any trader outside the UK and they'll look at you like your insane!