Five countries, real residential connections, right now — no account. A data-center ping says "up"; a real user in another country can be looking at a block page.
Countries refer to route settings. We observe the site response through those routes; the country of the actual exit is not independently verified.
The free check requests a public HTTP response through residential proxy providers. It samples selected routes, not every user or ISP. Limited to a couple of runs per hour per visitor.