said by FFH:Interesting paradox between your statements here and your signature. Your signature indicates you're for "less government", yet you want the government micromanaging the internet with a system more draconian than the Great Firewall of China. Do you enjoy hypocrisy?
They can implement filters in the ISPs routers to throw in the bit bucket any traffic going to or coming from the PirateBay's IP addresses. And they don't have to depend on DNS to know what those IP addresses are. They can start there, but then also block any IP address that they find are being used by ThePirateBay not in the DNS records. If people can bypass DNS systems to find &reach the PirateBay, then the ISPs can also find them and block them.
And yes, people can use proxy servers, but those can be blocked too, if they want.