I made an account just to reply to this.
I noticed the same thing here, in Canada, and a buddy in New Zealand said he witnessed the same. Except it continued for weeks after the protests ended. Loud fireworks, sometimes only setting off a puff of black smoke instead of colorful sparks, usually late at night - often too long after bar closing for drunk people to be a viable explanation.
Interestingly, I made a similar thread on ATS, and was met with aggressive denials by accounts with minimal posting histories. OP seems to have had a similar experience here, to some extent, and it made me wonder if we hit a nerve.
Depriving people of sleep seems a bit petty, though. I highly doubt that's a viable explanation. Neither would signaling...radio and the internet are perfectly fine. Maybe a dispersion method for infectious agents, if you know what I mean?
Then again, I have no hypothesis, so it's as good an explanation as any. It just kinda sounds like it was formulated by someone's insomniac racist grandpa. I just have a hunch that there's something here that's escaping notice.