Am i missing something?

I recently bought a monitor for my macbook so i could use it in clamshell (is it called that?) mode and a mouse and apple keyboard, and i was going to make a stand over the next few weeks to hold the macbook vertically so it takes up less space. I was going to base it on something like this;

http://www.amazon.com/Deskstandz-Premium-Vertical-MacBook-unibody/dp/B002WKOTQW

Of all the ones I've seen the manufacturer has placed the vents facing down. Now unless I'm missing something, why would they do that? Surely it would be better to have the vents pointing upwards, as heat rises and the other way round would result in the components getting fried?

So my question is, would I have to make mine facing down, for some obscure reason, or for the health of the moving parts in the laptop, or could I make it pointing upwards?

 

Ha looks like i just answered my own question, silly me. In every other stand I have seen, and every other manufacturer has put the vents pointing down.