Let them show their flags for that is what will get Americans riled, it was discussed by all the groups involved in organizing this to use American flags for the other's have bad perception
As someone who might immigrate to the United States legally, and who knows how difficult it is to do so, these people make might blood boil.
As a citizen of the Anglosphere - who believes that Anglo-American culture is superior and must be preserved for civilizatio to be preserved - I watch these people with their flags of a dirt-hole nation violating America and sometimes I fantasize about the Winter Palace in January 1905.