Is it ever polite to say "Move out of the way!"?

[BleedyGhoulzombiez]

Even if you prefix it with "Could you" or end with "please?"

I suppose it depends why and where ?

Generally, "excuse me, please" suffices.

Unless they are stupid slow sods who are holding everyone else up.

No, never polite :)

Probably never polite, but certainly acceptable if the person who is standing in the way shoud have the sense to move without being asked!

If the person you are saying it to is in imminent physical danger, then yes. Otherwise, no.