Good thread re: this on 8aNu, thread=pactice and ethics.
Basically if you go up and clip some bolts and then downclimb to the ground before the send then it may still be regarded (in some circles) as a legit point. If they are preclipped by someone else or with a stick then not. Obviously if its a matter of safety then make an exception and claim the point.
My thinking is that downclimbing is BS as you step off the rock, hey if you touch the ground attempting a boulder problem thats your attempt over! However I also think that how you protect yourself is arbitrary, what matters is doing the moves, but this goes against current trends so I dont expect too many will agree with me there. Its your game make your own rules, unless youre opening cutting edge routes, I doubt anyone will care what style you used, except maybe you!