Request for Steam keys for free game - is this a scam? [closed]
You should direct their inquiries to Steam Support.
Whatever issues they are having, you giving them a key isn't a solution. They need to contact support to resolve whatever they are experiencing.
In addition, your research shows there can be potential issues with giving them keys so there's no point in contributing to that.
Just like in Finance SE, you don't need to understand the scam; just avoid it.