There will be demonstrations tomorrow in Bangkok. The crowd might be as small as tens of thousands, or maybe huge as in millions. The airports and malls all will be open like normal. The protestors are peaceful but traffic could be difficult downtown. You will have no problems with the protestors. I have spent months with them. Just smile and keep on doing your thing. There is a chance of violence against the protestors but if that happens it likely will be a small attack that is over quickly.