At the risk of being put on the spot here, I would interpret “deem” as meaning there's a presumption. I'm trained in both common law and civil law—but as we would say in civil law,
a presumption can either be challengeable or unchallengeable.
In other words, presumptions in certain circumstances can be overturned, and that's the case here I would say. It's really a question of context, what you're looking at in the situation. It's hard to answer just like this in general terms.