They don't even need to detect proxies. When you sign up for Netflix you give them billing information. If you are a Canadian customer, they can always show you

They don't even need to detect proxies. When you sign up for Netflix you give them billing information. If you are a Canadian customer, they can always show you Canadian Netflix no matter where you are. Otherwise, if they want to let you travel and take Netflix with you, they don't need to block 100% of proxies. They could probably automate detection of the most common proxies and VPN services. They care about the lazy 99% of people who won't go to great lengths to evade the system.