Ah, I see where you are coming from now. I'd just ask the question whether stealing Source/souls is a mechanical or role-playing choice. I suppose both is the answer, but it's more of a mechanical one in this scenario. This logically leads to the question - "why would they make stealing source so overpowered that we need a role-playing deterrent and mechanical disadvantages?". I think balance is the key here, rather than any interface reaction. There is also the idea of too much deterrents. If they make it too punishing (though punishment in games is a concept I'm rather against) then nobody would do it. I just think they should restrain the combat advantages of source, but make you more detestable by good characters the more you eat souls. That way you aren't way overpowered, but also retain the role-playing element.
