Here is more from the Washington Examiner:
Around 200 protestors flooded into Heritage's Capitol Hill headquarters an hour before noon Tuesday, screaming that they were going to shut down the think tank. While opposition to Trump's budget was the headline of the demonstration, they didn't let that stifle their creativity. "Our solution to pollution is the people's revolution," they chanted before switching over to the more succinct, but no less vague, cadence of "water not walls."
Regardless of the mixed messaging, the bottom line was simple. They swarmed into Heritage because they didn't like the ideas the think tank produced. And instead of trying to help reach consensus with traditional protest, they tried intimidating the opposition.
The flash anarchy strategy appears to be organized by an organization called the People's Action Institute. And while that group certainly has great passion they demonstrated very little endurance. They were in and out in less than 20 minutes.
That was just long enough for the whole stunt to ironically backfire. Heritage ran a full court press on the protest. They posted a live stream of the protest, used the event to plug a policy paper, and their staffers offered a dozen snarky takes on Twitter. The Daily Signal (where I used to work) will no doubt flood the zone with coverage.
Here is what Brietbart had to say on the incident, including pictures from inside and outside the think tank. Here are a few videos of the event from The Federalist.
Here are some statements from the Heritage Foundation about the incident.
Protests inside of think tanks are extremely rare, and the only recent parallel that Think Tank Watch remembers is from last year when violence erupted on "Think Tank Row" as Turkey's President was speaking at the Brookings Institution.