What if Glorfindel joined the fellowship to Lothlorien?

[William Cloud Hicklin]

Originally Posted by Inziladun

The Witch-king would have been much more likely to recognize Glorfindel than Sauron, as one would think he did when the Black Riders were driven into the Ford of Bruinen. And you know, maybe that was another strike against Glorfindel being included in the Fellowship.

But only if he saw him. It's not like Glorfindel radiated some sort of Arda-wide homing beacon! Moreover, any Wraith would have, if it saw a High-elf of Valinor, immediately recognized him as an enemy and a threat even if not as a particular individual (and likely withdrawn, as Khamul did from Gildor's party).

If Glorfindel had been seen or otherwise discerned as associated with the Nine Walkers, wouldn't that have been a clear indication the Ring was also there?

Not necessarily: Glorfindel, I'm sure, was known as one of the chief foes of Sauron and might be expected to engage in scouting missions (as he in fact did in the search for Gandalf). Moreover, we see from the Galdor episode that the presence of High-elves tended to confuse Ringwraiths' senses and actually mask the Ring's "signal."