When you talk about acts of treason, acts of war, ultimately you're implying that they've automatically made a decision to renounce their citizenship. I'm trying to come up with an example, and the first thing that comes to my mind would be Afghanistan, where you might have some Canadian citizens protesting very aggressively against the Canadian Forces being physically present in Afghanistan.
Le premier exemple qui me vient à l'esprit, c'est les citoyens canadiens en Afghanistan qui pourraient protester avec véhémence contre la présence des Forces canadiennes.