Wake-Up Slap can hit my Staraptor while it flies...?

[Heald]

So I was playing Diamond today, levelling up my Staraptor, when a wild Machoke appeared. I commanded Staraptor to fly and expected Machoke's attack to miss. Oddly enough, he used Wake-Up Slap and it hit Staraptor while she was still airbourne. While this had little consequence in of itself, has anyone else noticed this bug, or was it a one-off?

[RattataGuy]

Machoke has a new ability called No Guard (http://bulbapedia.bulbagarden.net/wiki/No_Guard_%28ability%29). "All moves used by or against a Pokémon with this ability cannot miss." Even against a Flying or Digging pokemon.

[Blademaster]

Does this include Pokemon with type immunities? I.e., can that same Machoke's Wake-Up Slap strike a Misdreavus or a Dusknoir?

[Weasel Overlord]

I'd have thought that it wouldn't make a difference for those type immunities, cos the text is different, isn't it? If an attack misses, doesn't it just say "missed" and if there's an immunity, it says "so-and-so is not affected" or something to that effect, right?

[Negrek]

No guard does not negate immunities.