Prone then Teleport/Move (Slide, Pull) = Still Prone?

[keterys]

And, of course, many games don't allow you to teleport into midair (offensively or defensively) so that you fall to trigger the boots/neck. If you go that route, verify with your DM.

 

[KarinsDad]

An acrobatic stunt is a Standard or Move Action. Sure sounds, to me, like something that is supposed to be used on your own turn and not as a reaction to something.

The OP mentioned Eladrin Fey Step and the Assassin various shadow walking abilities. These occurs on your own turn.

When did we change the discussion to a reaction?

And, of course, many games don't allow you to teleport into midair (offensively or defensively) so that you fall to trigger the boots/neck. If you go that route, verify with your DM.

Be that as it may, it is allowed by RAW.

If arriving in the destination space would cause the target to fall or if that space is hindering terrain, the target can make a saving throw. On a save, the teleportation is negated.

 

[keterys]

That rule applies equally well for squares over a pit trap or off a cliff. Much like how the conjuration rules that prevent conjurations from triggering pit traps and falling into them are construed to allow people to create conjurations directly over a creature's head, the rules are a little less clear _because the rules don't deal well with three dimensions_.

Hence, there's a lot of table variance. So whenever you want to do anything that relies on manipulation of three dimensions, you really want to check with the DM first. And good luck with that in LFR...