Just a hypothetical one, but Skills are only considered slotted and any passives applied, when the skills bar they're slotted in is the active one.
Some Assassination Skills apply a small passive health increase for each skill slotted; I have a couple slotted in my primary weapon Skills bar, which gives a small health boost but I could conceivably have 6 which would give a more significant boost.
I have no Assassination Skills slotted in my secondary weapon and, from my character screen, I can see a slight health drop when I swap weapons.
As mentioned above, there could be situations where a noticeable passive increase to health could be gained which could lead to a situation, in low health instances, where swapping weapons could actually drop health below zero. It's probably never happened, but I'm just intrigued as to whether this could actually kill a character or whether there's a mechanic built in to block weapon swapping in this, potentially embarrassing situation.
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