She has had a history of mild illegal activity, including robbery, hinting at her less than noble nature.
Tails flew out of his Sea Fox and fell in love the moment he laid eyes on the robotic replica of the younger Fiona Fox and untied her.
Christien: with the Freedom Fighters, why do you ask? After they broke away, Tails told his lips to move, to say anything at all.
Fiona accompanied the Freedom Fighters to the Nanite City to rescue Bunnie, and was wary of working with to prevent the nanites from spreading.
Together with Scourge, she came bearing bad news: not only had the decided to attack Echidnaopolis, but the warring factions of the Dark Legion under Lien-Da and Remington had put aside their conflict to stop Finitevus' plans to resurrect Enerjak, the arch-nemesis of Knuckles the Echidna.
Fiona tried as hard as she could to convince them to let her in, but they weren't biting.