My understanding is that Parler's terms of service already included a prohibition against illegal activities. The question then becomes, does an up-an-comer social media service dedicated to encouraging free speech have the resources to handle a sudden flood of Twitter refugees? I'm perfectly willing to believe the answer is no.

I saw a representative of Parler being interviewed. She said that they rely on users reporting violations. Perhaps that doesn't scale. But it's unreasonable to think that the problem could be addressed, given 24 hours to do so.

If anything, malicious actors on Parler are second-rate amateurs. Whoever thinks organizing an uprising on a public platform that requires two-factor authentication (via ones cellphone) to join is doing the work of the police and prosecutors for them. If the tech giants and government were really so worried about this, Parler has just created for them the greatest honeypot for simpleminded, would-be insurrectionists ever. And they do have the resources to capitalize on it.