We never know for sure whether it's in the community undetected. We saw that after the last lockdown. Virus was being detected in waste water despite no reported positive cases.
That's why we have lockdowns. To prevent unreported/unknown cases from spreading excessively.
Given that some of the protesters were antivaxxer and/or anti lockdowners, we don't know what their movements were prior to the protest. If someone had picked up Covid and had not developed symptoms, they could have easily spread it to others.
I also think that if some of those protesters developed symptoms after the march they are probably not going to report it.
Hence, the virus might get a head start and away we go again.
