Inserting Hard Drive Upside Down

I was just wondering if anyone ever heard of a person experiencing problems because they used a hard drive physically upside down in the case.

I can use a single Sata cable to power my HD at the bottom of the case and my DVD drive at the top if I can flip the hard drive upside down, because of the way the cable is keyed, but if I have to use it right side up I would have to use 2 cables for this which I would rather avoid.

Basically, unless anyone has heard of or experienced a problem of this nature, I will be the guinea pig to try it upside down and see what happens.
i have put them in upside down and vertically before with no issues

for the same reason--only having 1 sata power cable available with 2 connectors on it
Well, the thing that I was thinking about is more that the write heads are a few nanometers off of the platters and gravity might be pulling them in the wrong direction if they are upside down.

I doubt it would scratch the disk from being upside down, but that is the main worry at the moment.