The media will probably have those few walking around in a tight circle with a close up shot to make it look like many more.
You'd be surprised at what Hollywood can do with computers today.
The usual Communist trick. I was just a kid but I remember the 1948 May Day parade in NYC. Seemed like a lot of people marched by until my dad said they marched from Columbus Circle down about 10-15 blocks, then got on the subway, rode back up to 59th St and joined in the rear of the parade.
An old lasy across the hallway from us was a Communist and usually left "The Daily Worker" lying in the apartments vestibule in an attempt to convert people. I remember the headlines after the parade: "THOUSANDS march in the May Day parade, showing that support is growing for The Party!"
We wrote mocking jokes all over the rag and left it there.