lunabee34

I think it's less that they think she might go murdery or do something randomly criminal and more that Ross and the people behind him don't trust Wanda and what she can do the power she wields unless they control her. It's just... if Tony doesn't support locking her up just because she's powered, he sure certainly defends it.

On a related note, I've seen some interesting thoughts that one of the continuing themes running throughout the MCU is superheroes and the scramble by the existing powers that be to maintain top dog status.

Iron Man - first modern hero that publicly rejects the authority of the powers that be.
Iron Man 2 - various governments try to break Tony's monopoly on powered armour. Failure.
Incredible Hulk - rather than leave Banner to his own peaceful devices, the US Army pursues him in an effort to restrict his power as a free agent, and also so they can replicate it safely under their control. Failure.
Thor - The powers that be realise that there is a greater universe out there, with even more things that they don't control.
Avengers - Which leads to the attempted creation of Phase 2 weaponry using the Tesseract, which goes badly wrong. Worse, the Avengers are now popular heroes, limiting how much the powers that be can publicly move against them.
Captain America: The Winter Soldier - So they create the orbital helicarriers instead. And note that these are focussed towards the planet, rather than away, which would make them an excellent weapon to dispose of any troublesome powered individuals. But it goes wrong. SHIELD - the only existing main counter to powered individuals that the powers that be have - is destroyed, and Black Widow (amongst others) publicly flaunts the fact that the powers that be can't touch the Avengers.
Avengers: Age of Ultron - And then Sokovia happens. In the aftermath of this disaster, the Avengers' image is tarnished, finally allowing the powers that be the chance to start moving against them. Note that - given the size of the Accords - they must have had them prepared before Lagos. There is no way that sizeable book was assembled in three days.

Edit: I will admit I have a certain urge to write a fic wherein Wanda travels across the world after Civil War, using her powers to do random acts of good whereever she goes. It's not the wise choice, exposing herself, leaving the protection of the others, but she can't remain locked up again, another prisoner, however well meaning her jailors. And what use are her powers if she make some lives better with them, after all they've cost?

Possibly of a form where I weave between the news stories that she leaves behind her and small incidents as she experiences them. (And maybe have some femslash in there, maybe not.)