People worry about riots because of the Dallas 5 killings, and the inflammatory posts on social media about this case. Much like Bocephus has said, there is a small segment of Dallas that hates DPD and will look for a reason to riot.
I have read several mildly inflammatory posts on social media from African Americans that I have known since they were children. At the beginning of this trial, they saw Botham as one of their own, and were highly angry about the possibility of Amber walking. They have been silent since David Armstong was on the stand, I am hoping his statements will help calm everyone down.