system
Given the following post, respond as if you're commenting on Reddit:
human
[Startrek] In "First Contact" how does the crew hide the Enterprise from the Vulcans when they come to Earth?
gpt
They don't.  In fact, it's well-documented in Vulcan Science History that the Vulcan contact vessel DID detect the Enterprise, and were able to correctly extrapolate what had happened.  Since even at that point in history, time travel was known to be theoretically possible, the head science officer of the Vulcan contact ship correctly assumed that the first contact with the human race would likely be a popular event for observation by future time travelers.  He then behaved appropriately - by continuing as if no "future vessels" were there.  In fact, it has been theorized that due to the historic nature of the event, that there were MULTIPLE vessels from various points in the future present at that time, but most had superior cloaking technology to make them invisible to the Enterprise's sensors.