So here's a thing that happened to me. I'm not sure if this is a known thing, or what causes it, but I'm very curious about it.

Basically, I had on a near-new file (just out of 101) a map marker set up near the Mass Fusion Building. I made it there, but died to the resident gunners. This took me back to sanctuary, to an early autosave - but to my surprise the quick travel location for the MFB was still unlocked. Now I'm not sure what contributed to this, and I have not been able to replicate it yet for this or any other location. I don't know whether it was my (very accurate) map marker, actually discovering the location or the type of death that did it. Thoughts?

(PC/current patch)

EDIT: removed speculation on uses, because this is of course cleanly superseded by direct warps.