Zwift currently has a weight limit of 45 kilograms also 100 pounds. Many kids, like me do not weigh more than the limit, in fact some riders like me weigh much less than the limit(I\’m 29kg) So in order to know how many watts per kilogram you are actually doing, after a race you have to click on the results from the race. Parents, and kids themselves have been asking Zwift to fix/change the limit.
During most group rides there will be a sweep. A sweep is a rider that helps riders who fall behind catch back up to the group/leader. Group rides also typically have a barrier, also known as the fence. The fence removes riders who go way ahead of the leader for over a minute. These features/riders help keep the group a group ride. In any event there will always be a rider who goes ahead or chooses the wrong category. This is a problem Zwift is currently trying to fix.