Can special banners (boromir, gamling, halbarad etc.) be picked up if their original carrier is slain, and do they still have their special effects?

In OR, most of those banners specifically mentioned in their entry that they cannot be picked up.

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"I am the Flying Spagetti Monster. Thou shall have no other monsters before me"
-FSM.

Can you please provide me with a page reference because I can't find this?
I also don't have the new books so I am not aware if the ruling has changed but the ORB states that any banner can be picked up by a Warrior.
On the other hand, both Halbard and Boromir state in their entries that their banners have to be carried by them in order to provide their special bonusses, a case which doesn't stand for Gamling's banner since there is not such a limitation in its rules.
Nevertheless, I have always played it that if Halbard/Boromir/Gamling is killed then his banner can be picked up by a friendly Warrior but all the special bonusses are lost and thus treat it as a normal banner.