Ahh ... (one-upping evul scientist voice) ... but what vould happen herr doc'tors, if the Force Cage was created + still inside a Bag Of Holding, and then that bag was put into a Portable Hole?
*ahem*
The planar rift would occur, however, the force cage being inside the dimensional claudication will find itself on the astral side of the rift. Besides, there is no mention of the force cage being immovable. The only similarity with Wall of Force is the methods of destruction. Also, any means of astral travel can escape a Force Cage... so the planar effect might simply draw the occupants through the astral openings in the Force Cage, probably a somewhat uncomfortable experience, to say the least.
Ohh and and , what vould happen if the Wizard had a Dimension Lock cast on him before being put into the Force Cage?
A dimensional lock does not protect against planar rift or planar breech effects.
Should the DM wish to allow a check anyway, the dimensional lock effect would have to beat the spell DC equivalent of the rift/breech's strength under the clause of directly conflicting effects. Even if the result was ruled to succeed, once the dimensional lock effect wore off, the end result would be the same.
