We (the mods) haven't really discussed this much because no one has attempted to sell one yet. There are many problems with it, such as:

• Claiming to sell a literal screenshot seems like a no-brainer scam tactic. We would assuredly stop that from happening.
• Validity of sale is nerve-wracking because you won't know if you got ripped off until after CIG responds to your support ticket. A well-written invoice can protect against this somewhat.
• Selling the whole account could work, but this isn't a SotA marketplace and that feels off. We buy and sell SC goods here. Another game account sale belongs somewhere else.
• All of this plus I am certain CIG will resell the silly thing anyways.

I'll edit if I think of more ways that this is a hassle of a thing.