Why was Boromir allowed to join the Fellowship?

[William Cloud Hicklin]

Originally Posted by Inziladun

True, but Boromir's words to the Company seem to indicate he would have been at least a bit irritated if he had had to go to Minas Tirith alone.

FOTR The Great River

As much as Denethor loved his son, he might have seen Boromir returning by himself as a slight, which could have turned him even more against the thought of accepting aid from anyone but the Rohirrim.

But the context by the time of that debate was wholly different. Gandalf had fallen, Aragorn now had responsibility for Frodo and the Quest, as opposed to his original plan to go to MT with Boromir, and at any rate Boromir had declared from the beginning his intention to return home, where he was needed. At this point of course he is trying to make an argument for the whole Company to go with him- in which it must be said that Ring-lust might have been a factor by now.

I don't think Denethor would have seen much of a 'slight' in what was conceived as in essence an into-the-blue reconnaissance; Boromir was sent off to find "Imladris," about which even Denethor hardly knew anything, even where it was, save that "Elrond and Half-elven once dwelt" there. He wasn't expecting allies or even a solo Great Hero, just an answer to the riddle (and the sudden reappearance of 'Thorongil' would hardly have made him happy!).