And what I mean with that is simple, if you would add too many followers your account can be terminated which wouldn't be good at all..
According to the rules of Twitter;
- If you have followed a large amount of users in a short amount of time;
- If you have followed and unfollowed people in a short time period, particularly by automated means (aggressive follower churn);
- If you repeatedly follow and unfollow people, whether to build followers or to garner more attention for your profile;
...your account can be suspended if one of these things are done.