Switzerland
Practice Relating to Rule 154. Obedience to Superior Orders
Switzerland’s Regulation on Legal Bases for Conduct during an Engagement (2005) states:
6 Subordinates do not carry out an order if they know that it is punishable according to national or international law. In case of doubt, they ask their superior for further information.
…
245 … [Subordinates] do not execute any order of which they know that it violates the law of armed conflict. If in doubt, they request further information from their superiors.

[emphasis in original]