1. OVERWATCH ATTACKS AGAINST FOES BEHIND COVER
REASONING
The spirit of the Overwatch rules seem to be that it’s “targets caught in the kill zone”.

• This prototypically includes a target using a Movement action to enter an attacker’s designated “kill zone”, commonly unaware & typically without cover.
• Secondarily, this also includes guarding a prisoner. You sit them in your “kill zone” unarmed & without cover.
  What does not seem to fall inside the spirit of this rule is an Overwatch attack on an armed foe already behind cover (and is not attempting to leave it).

If during a firefight, a character’s foe is unseen behind their cover, I don’t see a problem in using Overwatch to simply wait until they’re visible to get your shot off for your Turn (assuming they at some point during your Turn are visible). However, since the armed foe is behind cover, not using a Movement action to leave cover & is well aware of your presence – it’s hard to make the case that you’ve “caught them in your kill zone” and therefore why they’d get no Dodge & have to make a Pinning Test.

RULE CLARIFICATION
If an Overwatch attack is made on a target already behind cover (and they’re not in the middle of a Movement action to leave it), then it does not take away the target’s Dodge, nor does it force them to make a Pinning Test.

2. OVERWATCH PINNING PROTOCOL
A character performs a Movement Action into an Overwatch kill zone.

• If they pass their Pinning Test – they can finish the Movement Action they were in the middle of when they entered the kill zone.
• If they fail their Pinning Test – they lose the rest of the Movement Action they were in the middle of when they entered the Overwatch kill zone. However, if they still have a Half Action left in that turn, they must use that to reach cover.