The logistics of transport leaves tracks. They're mostly going to show up in buses. THere's no parking for cars, and they're not flying or walking.
So, the bus fleets have been rented (Idon't think most of these protesters are getting Greyhound tickets and paying themselves). The license plates can be tracked, and large charters traced.
They have to be fed. They have to sleep somewhere. And both restaurant and hotel activity are still restricted.
Rose City Antifa FROM YEARS AGO
https://www.reddit.com/r/Portland/comments/2m0oux/rose_city_antifa_quit_being_douchebags_or_get_the/
“The majority of them wore masks and black hoodies, and many were armed with wooden rods and some with knives. Not twenty minutes after doors the antifa became violent, assaulting Alhambra’s security and show-goers, even grabbing a random person from the line and throwing them in front of a moving car. The security officers took countless punches to the face and body as they protected the line from the out-of-control assailants. Had the police arrived any later, people would have undoubtedly been seriously injured. ‘
How many buses = 1M protesters?