Actually what happened in Virginia could have been prevented if the locals had done their duty, i.e. keep the protesters in the areas they had permits for.
What training have you had in crowd management?
None, but even a novice can see the cops clearly didn't keep the two sides apart.
Crowd control was in effect, but was not effective. After action reviews will produce what went wrong and how. No weapons or defensive apparatus should be allowed within a perimeter where a permit has been issued, and each permit should be evaluated and rated, the more likely for an incident, the greater the cost of the permit.
Within the perimeter, which should exceed beyond the scope of the permit, loitering or acting suspiciously in the opinion of sworn LE, uniformed or not, shall be asked to submit to search and seizure, or if unwilling to do so, s/he shall be checked for weapons (pat down) and after providing required ID be told to leave the area, or be subject to arrest.
Anyone found to be in possession of a dangerous weapon, see:
2005 California Penal Code Sections 12020-12040 :: :: :: Article 2. :: Unlawful Carrying and Possession of Weapons
should be charged with a felony, and suffer the full penalty as warranted by the law.
BTW, the link has one mistake. No one charged and convicted of a single crime can be sentenced to county jail for more that 356 days. A sentence of 3 years is a commitment to the St. Prison.