The more physically all-encompassing the shielding is that is being used as a de facto Faraday cage, the more effective the shielding is likely to be to protect the RFID chip from being scanned.

While it's possible to use say separated towers of sorts to get some of the same blocking benefits as a box/bag used as a Faraday cage, there is a reason why government-secured electronic devices at risk of remote wiping by RF contact are placed in Faraday boxes/bags and not merely between just two planes of material for RF interference.