I know that if a user is added to a SharePoint group, a crawl needs to run before the ACLs are updated to reflect the new user's permissions.
The question that my team is debating is whether or not those crawls are automatically kicked off by the action of adding a user to (or removing a user from) a group.
My contention is no - the crawl does need to happen, but it will happen either at the next scheduled time, or if someone goes in to the Search Service and starts one manually.
Another team member says that the crawls start automatically after a user is added or removed from a group.
Can anyone shed any light on this?