This was an undocumented addition. I'm trying to design immersively, and that means calling attention away from the mechanics. When I use a teleporter it looks like an object that would logically grant access to another location, so logically that it's possible to suspend disbelief that it's not a prim with a script in it. It doesn't look like a chair, it doesn't look like an incongruent ball, and it doesn't hover text that says, "Look at me, I'm a Second Life sittarget that simulates teleportation'.
Is the promised llTeleportAvatar almost here? Or can this cleverish but unnecessary feature go away? Because I'm hard-pressed now to make that transition feel like it belongs in a natural environment.
If someone redefined the SITTEXT, would it be intuitive for the UnSit message to then say 'Cancelled <Revised SITTEXT>', or would it be counter-intuitive if the UnSit did exactly what the SITTEXT suggests?
And while I'm bringing up llTeleportAvatar, can it please not request permissions if the object is owned by the land owner? The land owner should be able to teleport anyone freely, and I'm trying to use teleport in unobrusive ways. Now that unseating sittargets notify users that they're no longer sitting when the object is most obviously not a seat, couldn't a true teleport function perform that task without telling the users, 'Hey, I'm a teleport function!'