iWhy isn't any effort made to be able to identify protestors in the event of murder and violence? I simple high pressure water cannon (more like a long range squirt gun than knock-you-down-gusher) with an alcohol based purple ink with an unique smell would allow tracking and identifying anyone for at least 24 to 48 hours - yet harm no one. Fire departments have such high pressure long range pumpers - max range about 100 yards depending on the wind. Dogs could track it (or now electronic sniffers) and the person obviously identified.
Since many of those governments don't really like radicals and troublemakers - and all the extreme social, religious and political divisions, it likely they would more fear reprisals from their own people.
(That and back up the water cannon with a couple of mini-guns. Hey, they could even be loaded with rubber bullets - 6000 a minute. )