Setting aside for a moment the question of 'when,' HOW do you think the GJ results will be released? How do you think they SHOULD be released? What precautions would you take either way to ensure that reactions are as calm as possible whichever way the verdict goes?
What I hope is that LE will be given a heads up as things are wrapping up, then notified again when a decision is made when the announcement will be released. That way time off is managed, they have time to get in place, and can notify business owners, particularly those targeted. I'm thinking there will probably be a press blurb that a decision has been reached and will be announced at 2 PM, for example. I'm guessing National Guard will be given a lead time so if they prove necessary, personnel and gear is available. If I owned a business in Ferguson, I'd make sure my insurance and any riders were in place, that boards and helpers to get them hung ASAP are already in place, and have a bug out bag, and plan of how the family will assemble elsewhere, safely. I hope it's announced after school is let out for the day or on a weekend, so kids aren't stuck in school on lockdown. Barring a miracle, it may be a huge mess, although I do think the majority of residents won't riot. I can't imagine what will happen if rioters block roads and peaceful people can't flee.
ETA: I'm guessing all LE across St Louis will be on call, and their families away from their homes, given the dox'ing by Anonymous and death threats. If I were one of Wilson's neighbors, I'd stay elsewhere too when the verdict is in. IMO, the main thing is LE needs max lead time, biz owners need some lead time, and the law abiding public will need time too. Traffic out of areas could be an issue too.