I would advise most members to post little to no Microsoft Account sales within the next couple days. You guys need to have patience. Do not risk anything. Unless you do not really "care" for the account then feel free to go on with your sales. After a week or so if the Banning of accounts has stopped or lessened then post sales threads, but post asterisks within the initial Gamertag (Hint about Gamertag Meaning and if people aren't mentally disabled they will get it) and have people PM you for proof. After a Month or so when Banning has officially stopped then continue with your regular sales.
During this whole time do not show proof or tell your Gamertags to anyone who has only 0-10 posts and hasn't been registered for more than a couple days to a week. This will prevent Microsoft Employees from PMing or Contacting you asking for the Full gamertag. I personally have turned down multiple new members contacting me about some of my Gamertags today.
Lastly, go through all of your old threads and EDIT out any of your gamertag and the proof and any of your posts mentioning the Gamertag. This will prevent Employees from looking through your past threads and banning your Gamertags.
This is in no way a "MS is watching us" or "FUCK Microsoft" Thread. From what I know this is the best possibly to prevent getting banned.
Merry Christmas.