Does blindsight or tremorsense count for line of sight?

Question

If I have tremorsense or blindsight, do I have line of sight if I'm otherwise blind?

In particular, would this allow me to teleport out of a Stinking Cloud?

Answer 1

Blindsight notes that:

A creature that has blindsight can clearly see creatures or objects within a specified range and within line of effect, even if they are invisible or obscured. The creature otherwise relies on its normal vision.

Stinking cloud:

The burst creates a zone of poisonous vapor that blocks line of sight until the end of your next turn.

And teleportation, of course, explicitly requires line of sight.

The significant problem is that "line of sight" is never formally defined. I believe that line of sight is determined through these determining cover rules:

Getting Technical: If you need to be extremely precise, choose a square the attacker occupies and a square the defender occupies. Draw an imaginary line from every corner of the attacker’s space to every corner of the defender’s space. If even one line is obstructed, the defender has cover. (A line [t]hat runs parallel right along a wall isn’t blocked.)

Thus, line of sight is any unbroken line running from a corner of the attacker's square to a corner of the defender's square. Stinking cloud blocks that, but both blindsight and tremorsense allow the penetration of "obscured" (through environmental effects like darkness).

The question to pose to the DM: does the stinking cloud magically jam vision modes or is the blocking of line of sight a function of the production of the Heavily obscured effect:

"Heavily Obscured: Squares of heavy foliage, heavy fog, or heavy smoke are heavily obscured."

Answer: probably, but ask your DM based on the nature of obscurement that stinking cloud provides.

Answer 2

Yes, but quirkily, by RAW you can't teleport there.

The compendium entry for Blind^DDI says

A blind creature relies on special senses, such as blindsight or tremorsense, to see within a specified range

Neither it, nor the blindsight and tremorsense entires mention line of sight specifically, but I think being able to "see" should grant line of sight.

However, both blindsight and tremorsense allow you to see "creatures or objects within a specified range" which doesn't seem to me to give you a valid teleport target, as to teleport you need line of sight to a square, and so you can't use blindsight or tremorsense to see a destination to teleport to.