Here is another thing to consider: People complain about buying "Premium" keys that sellers marketed as "Will not be resold." The buyer uses the key, and while s/he never hacks, one day the key gets banned. That seller must have resold it right?
Maybe because I am optimistic about humanity, consider the following: A legit seller makes a youtube video to steal someones key. The person watches the video, downloads link and key gets stolen and sold, not to be sold again. However, that person is persistent and watches 3 more youtube videos trying to "hack" in Dayz. Now 3 more sellers have those keys and they each sell it. Maybe one of those people hacks with it, now the 1 key gets banned. The first person bought it was a "premium" key and now thinks the legit seller has resold it.
Just something to think about.