Having random people, doesn't matter if they are local residents or not, enter and explore an active construction sites is an absolutely terrible idea. Doesn't matter if it's after the workers have gone home for the night it's an absolute liability nightmare on both sides, the person could get seriously hurt/killed or the person wrecking something that would could run into the millions to fix.That is not, in fact, how it's supposed to work.And complaining about residents monitoring/measuring a public works project in their neighborhood? That's how it's supposed to work.
Not to mention there is an active train line right there as well, their decision could have easily turned disastrous for them. Anyone who enters an active construction site that doesn't have permission to be there needs to held responsible for their actions and "oh nothing went bad" isn't a legitimate defense