[cellurdur]

Originally Posted by William Cloud Hicklin

No, actually Tolkien explicitly denied that the Gem was a "ticket" or that Arwen could simply "give her place on the boat" to Frodo. Its purpose, as mentioned above, was as a symbol and token of hope that Frodo could cling to in his dark moments, a reminder that there was a Way Out. The exception to The Rules by which Bilbo and Frodo were permitted into the West- something granted previously to no other mortals, ever, except possiby Tuor and in his case if the legend was true he was 'converted' to an Elf - had to be granted by Authority; in this case the Authority was the Maia Olorin, as Tolkien said Manwe's plenipotentiary in Middle-earth, who also went with them on the ship so there wouldn't have been any holdup with Customs....

Bilbo and Frodo, and later Sam (and perhaps Gimli) didn't go to live in Valinor proper (which as Tolkien points out would be unendurable torment for a mortal), but on Tol Eressea, Elvenhome, an 'undying' land which yet had something of Middle-earth about it, a place where returned Elves felt more at home. This was not permanent. Hobbits did not gain "immortality" from being in the Undying Lands any more than Ar-Pharazon could have. It was conceived by Tolkien as a place of rest and healing, before in their own time they accepted the Gift of Men, much as Aragorn eventually did.

Perfectly summed up. Will just add letter which your information comes from.

"It is not made explicit how she could arrange this. She could not of course just transfer her ticket on the boat like that! For any except those of Elvish race 'sailing West' was not permitted, and any exception required 'authority', and
she was not in direct communication with the Valar, especially not since her choice to become 'mortal'. What is meant is that it was Arwen who first thought of sending Frodo into the West, and put in a plea for him to Gandalf (direct or through Galadriel, or both), and she used her own renunciation of the right to go West as an argument. Her renunciation and suffering were related to and enmeshed with Frodo's : both were parts of a plan for the regeneration of the state of Men. Her prayer might therefore be specially effective, and her plan have a certain equity of exchange. No doubt it was Gandalf who was the authority that accepted her plea. "-Letter 246