We have griefers using the ‘invite’ and ‘drop group’ features to abuse liminal boundaries.
A good example of this is The Lift on the Barrens/1000K Needles border.
We have griefers who repeatedly phase in and out from the boundary at the top of the lift. They are very intentionally abusing the layering mechanic. Some griefers are spending hours doing this.
The solution is simple. A 10 minute layering CD. Problem solved.