"Your VPN provider's IP address is public information. A quick subpoena is all it would take to reveal your identity. Seems like a risky way to watch Game of Thrones. At least on Usenet a download is just a download."
A subpoena can only work if the VPN services keeps logs of its user's transactions. Some do and some don't. Without logs there is nothing to subpoena. When evaluating a VPN it is very important to find out whether or not they do. As of now U.S. VPN's cannot be forced to keep logs.
A well regarded resource for such evaluation is:
https://torrentfreak.com/anonymous-vpn-service-provider-review-2015-150228/
A non-logging VPN with end to end encryption is absolutely required for safety using anything that transfers copyrighted material without permission. That includes both versions of Popcorn Time. Not taking this precaution is very, very expensive.