Autodecline Loot as Default
Open eq2ui_mainhud_persona.xml in NotePad.
Near the start of the first line of code you should find the following...
Code:
DeclineLoot="false"
Change the value from false to true.
Note: The checkbox will still show as unchecked and will require you to first check it, then uncheck it to disable Autodecline while in-game.