Yeah I've heard that myth quite a bit.
A cobra wants to warn you off so it raises itself up (usually near eye level if it can) and flares the hood. If it is going to strike, it'll *want* to strike out in front of itself.
However, they can tilt and strike up. They may end up falling over because of they way they position, flatten out and raise up, but yes, they can strike up. (they also don't have to be raised up and flared out to strike)

Here's an interesting thread where someone else had the same question if you want more feedback from others:
http://www.fieldherpforum.com/forum/...22718&p=250748