I've heard no evidence that Stephen didn't voluntarily choose to ingest those leaves.

If Saddam Hussein is not prepared to disarm himself voluntarily, ... then we have no option but to do it by force.

It's something I had never heard before Magruder made it, and I can't say that I have any evidence that [he is] right,

He did voluntarily appear and give evidence as a witness in an ongoing homicide investigation.

(There was) no negotiation at all. The only contact was because she wanted to voluntarily surrender.

Students come voluntarily to the shop and choose a bike. At the end, they leave with a bike they built themselves and the skills to [maintain] it.