Slightly Live said:
You'll see idiots with the jet pack trying to get this achievement over playing the game properly. If you wonder why in future there seems to be an increase in low-altitude jet-packing morons, you'll know why.
A splatter spree with a ghost, eh? Watch teams fight and betray over who gets the Ghost each time. Fun!
In other words, "Let yourself be killed and then try to take the enemy that killed you with you as you die!". If someone had told me this was going to be an actual Halo achievement yesterday I would have laughed. Now I'm just sad.
Multiplayer achievements need to be handled with care and like others have said these particular Achievements seem not to have learned from the mistakes of past Halo multiplayer Achievements and it's a shame. Nothing to get worked up about in all honesty but it's worth noting disappointment concerning them.
The jetpack one isn't really an achievement that can be done without actually playing the game how you would normally play the game. Just flying into the air for the sake of flying into the air is going to get people killed. But yes, I'm sure there will be idiots who focus only on the beat down achievement, and they will die a lot for it.
Really, I think most of the achievements will be fairly easy to do without thinking about what you're doing. For instance, running into someone on a small map and getting stuck by a player happens quite frequently. All you have to do is run into whoever stuck you and that achievement can be marked off the list.
And while a person can try and betray you for taking the ghost, that's a much more difficult task than simply betraying someone for getting to the sniper rifle first. But i tend to avoid BTB and Invasion, so that's not an achievement I'd even bother with.
As molekiller mentioned, most of these don't require any change in play style. They should happen pretty quickly. I'm indifferent to achievements for the most part. They're cool when you get them, but ultimately, they don't do anything other than boost an arbitrary gamer score. And if the achievements do cause some mayhem initially, from people playing differently than they normally would, it should calm down after a week or two, if that.