I don't believe it's country/region-specific, as I used my VPN to connect from all parts of the world (a few different Asian countries, South Africa, a number of different European countries including Switzerland and the UK, Canada, the U.S., New Zealand, Israel...) and every single one gets the same "Sensitive content warning" -> "Sign in to confirm your age" loop. Used a clean/private session for each new attempt, too. Best guess is that some people have a persistent cookie in their browser that is allowing them to bypass the sign in screen...for now, but probably not forever.