Voted yes to blacklist, but also cautiously. We've pretty easily identified the obvious "SuperAgentITK" types of in the past. There are people on here who are great at discovering and invalidating the sources somehow. It's more worrying that we debate about journalists who work for actual media outlets (although some of them are less than reliable, and may even be distasteful to some of us).
I'm reminded of a couple of things:
1) There was an article written by a very respectable journalist (can't remember who it was), that basically said they report what they from their sources, but that transfers are complicated, and things can change on a dime. These are sometimes intense and complicated business negotiations - which can fall apart at any moment. It would be poor form to judge some of these guys on their historical accuracy and blacklist purely on that basis.
2) Quite a few on the site can smell BS right off the bat. "Suarez to United." Honestly, we all know that will never happen.
3) Personally, I think a few things right now about our transfers. I think we do have some things pretty much wrapped up, and just because we don't see the signings on manutd.com just means the business is all but officially concluded. Van Gaal is under contract to the Dutch FA. If we start officially signing players, I'd assume that his press conferences for Holland will be disrupted. If we sign players at the WC, what is United going to do? Fly them out of their base camps in Brazil to Manchester at this point? Send down a medical team to interrupt the player's training? If we officially sign anyone while LvG is under contract, couldn't that be of use to the Dutch FA legal team if they have a horrible WC and seek to blame United and seek legal compensation from United? I'm no expert in legal matters, but it would seem United would want to shield themselves from unsettling any international FA organization during a World Cup, and also maintain good relations with those organizations for the future. So if a journo tweets "Luke Shaw is done before the WC", it may be true in all but the manutd.com announcement, we shouldn't just ban a journo from the twitter thread who said that.
Overall, I guess it's my opinion that the twitter thread should be fun. Sometimes outrageous, sometimes I'm really interested in a tweet and it truly is a precursor to actual transfer activity. Self policing and avoiding having 50+ posts arguing about an absolutely outrageous twitter post is what we should try to achieve, IMO.