Remember that there will be purpose in these promises of destructive and even violent protest (H/T Claire) around the inauguration. And the purpose is not about actually disrupting a party, or even embarrassing the new dictator-elect.
I would argue that it's a longer-term strategy. The Never Trump Army has invested itself way too heavily in the marketing idea that Le Coif du Orange will always, without exception, crack any head at the slightest dissent, and peaceful protests right out of the gate would not fit that narrative.
So: in order for Mein Trumpf to appear the proper oppressor in the opening and subsequent spotlight, he needs something to oppress. What more obvious than cracking down on "peaceful protestors" on inauguration day?
Really, it's the same logic that reminds us (thanks Kit Perez, via Claire) that if ATF really is on the chopping block (cuz...yeah, well, maybe), we should be completely unsurprised at another Operation Showtime any time now.
Sure, maybe nothing will go wrong--so many of these people are all-hat-no-cattle in the first place--but if something does: consider the idea that "the Brownshirts" do have to be seen being Brownshirts.