No dice, Disney. The way this works is if you want to use the tweets shouted into the ether, you can, and if someone doesn't like it, they can sue you, and then the US (and probably international) law gets to figure out on your dime via the lawyers you will pay whether you misused the tweets.

... or, Disney does the not-lazy thing, gathers up the tweets, issues individual requests to use to every user who tweets into the hashtag, and only moves forward with the ones they get consent for.

... or, third option, Disney puts up their own website where users can submit tweets by URL, and submitting a tweet to that website (signed off by a user's Disney account) confirms the user is claiming they own copyright of the tweet and is authorizing Disney to use it.

But yeah, more than zero effort on Disney's part required.

No, they don’t say that. They use ambiguous wording which could easily be construed to include any post they can see.