Battle For Gilneas Imprisonment Glitch-Easy RBG Win (Patreon)

The cage to the right of the waterworks flag in the Battle For Gilneas battleground can be used to imprison players. 

A teleport ability such as warlock shadow rift or death knight death grip can trap a player inside the cage. The cage removes line of sight from players so most classes cannot escape using special movement abilities, and are trapped for the duration of the bg. This is an automatic win in any close contest.

The easiest way to do this is to use a warlock with the "Kilrogg's Cunning" finesse conduit. 

Have the warlock stand next to the post on the gazebo nearest the cage and use eye of Kilrogg, facing into the post rather than the cage. The object of this is to get the eye to materialize inside the cage and put down a demonic circle inside, so you can port players with shadow rift. *

This will take you a few tries. Use small incremental shifts in movement to get the positioning correct. 

Death knights should simply stand next to the cage and grip enemy players- this is mostly trial and error. It is so sensitive to initial conditions that it requires luck however you position yourself.

Other class abilities eg ursol's vortex, sigil of chains do not seem to work-but I am still experimenting with these.

*If you cast the eye directly into the cage it will be deflected and will appear outside the cage. For some reason eye of kilrogg "deflections" from line of sight cause the eye to appear somewhat randomly nearby-the deflection itself sometimes ignores line of sight.