Here are some things I think I would do, if I were in charge, after declaring martial law in Ferguson, and nearby areas, as necessary.
1. Anyone arrested who happened to be from out of state would be returned to their last known address. If no address is supplied, we take you to Chicago.
2. Starting at 5pm, any group larger than 10 people, on streets, sidewalks, or parking lots, is arrested, and held for 24 hrs. Rule 1 may apply.
3. There would be some attempt at monitoring traffic into the city limits, perhaps with checkpoints, and/or checking local flop houses.