I was also there, but in my opinion 1.7M was an exaggeration. Don’t get me wrong, there were A LOT of people, the whole area from Victoria Park to Tamar Park was packed with people. There was also a constant flow of people coming in from North Point, a good 20 minute walk to the starting point.

Police estimates were definitely wrong, but the estimates from organisers are also always exaggerated, for the same reasons you mentioned the police estimates are wrong.