Use case: During group cycling rides, many participants reflexively start GPS recording as soon as they leave the house and stop it at the door on their way back.
When Strava detects a group ride, it could be interesting to automatically suggest splitting the activity at real start and finish of the ride. I think it could be done with current data (location correlation, still period). This would make it possible to have more representative data, such as average speed, since it wouldn't take into account the "commute" part of the ride. This function could take the form of a suggestion to split the activity, or to hide part of the activity. I think the majority of athletes would be happy to be able to compare themselves easily with the other participants just on the section corresponding to the group activity.
This could be a way of including a limited, assisted version of the activity breakdown functions in the mobile application. The interface could be very simple "We think your group outing started here and ended there. Trim, hide, do nothing?".
This would marginally increase confidentiality by making it easier to conceal where you live. This could be useful for runners and other sports.