Ground-based laser methane detection is sensitive enough to quantify hidden emissions, no matter how diffuse gas companies make the plume. Here's two companies operating in this space:
Yes, enclosed flaring is better than venting. However it makes it more difficult for third-party monitoring, the linked article mentions this:
>"If you enclose the flare, people don’t see it, so they don’t complain about it. But it also means it’s not visible from space by most of the methods used to track flare volumes.”
Sensirion: https://www.sensirion-connected.com/emissions-monitoring
Longpath Technologies: https://www.longpathtech.com