Technically speaking, many things you create (including a tweet) are copyright automatically and to use them commercially requires a license. In this case either MakerSpace needs some sort of agreement with the author of each tweet or they need to claim fair use in order to be able to legally display it. You give twitter license to reproduce your tweets (through the ToS) so they can host them for your friends, for example.
Practically speaking it's almost certainly not a copyright violation. If you see a sign "Use #HashTag to see your Tweet on the jumbotron" and then proceed to tweet at it, you've agreed to the licensing terms (that your tweet will be displayed).
The only case where this gets hairy is if you didn't know that using #Hashtag resulted in it being displayed on the jumbotron and didn't want that. If MakerSpace displayed every tweet with #DoNotDisplay or something like that, then they clearly don't have license and have violated copyright law.
Practically speaking it's almost certainly not a copyright violation. If you see a sign "Use #HashTag to see your Tweet on the jumbotron" and then proceed to tweet at it, you've agreed to the licensing terms (that your tweet will be displayed).
The only case where this gets hairy is if you didn't know that using #Hashtag resulted in it being displayed on the jumbotron and didn't want that. If MakerSpace displayed every tweet with #DoNotDisplay or something like that, then they clearly don't have license and have violated copyright law.