What if someone listens to packets going to and coming from HMA? They would easily see your traffic just as much if they simply monitored your Internet connection. Wait...what if they simply monitor your Internet connection via your ISP?
Anyone thinking there is any way possible to hide your Internet traffic has no clue how HTTP works.
The most likely scenario is they are going to see your activity on a website and track your IP address to the VPN. Unless the VPN service provider tells them the IP address they are mapping your traffic to, it's a dead end.
The key is that the VPN provider must be trustworthy.
That's my theory. I am more than happy to be disabused of it.