Peek at our Compliance team's 2018 Transparency Report. You can see why many businesses choose to block US users. Cost of handling subpoenas (regardless of licenses) is quickly becoming a barrier to entry. Inquiries up 3x YoY.
Sad thing is it's not even about licenses and the majority of requests aren't coming from regulators. Does go to show what law enforcement stands to lose if regulators don't get it right though.