I don’t expect the radical SHTF scenario, BTW, although default is likely. Remember cultural differences between the USA and less developed countries along with the fact that some of the events reported by Fernando were sporadic ones, mentioned in anecdotes about locations distant from his.
Others have mentioned experiences in Iraq, including one gentleman who described himself as a combat specialty veteran (said he was infantry, but who knows). The USA is not likely to have an ethnic civil war soon. Ethnic civil wars are far worse than other civil wars. Economic poorness alone is far less worse than either.
And you (all) may or may not have experience with having spent much time in a poor area of a poor country. Whole different scenario there. Generally peaceful but potentially frustrating and depressing. The technically inclined w/ rough, tough work ethics tend to do relatively well in those places and times.
I think our tri-racial cities are going to go Rwanda on steroids when the power goes out.
If the power is out more than a week, ALL bets are OFF.