RF shield needed for BLE SoC in PCB design
For CE (or the new RED now) is not compulsory to use a RF shield. Using a shield will help you with unwanted spurious emissions.

That is, if you are radiating at 2.4GHz by your antenna, from your PCB there will be unwanted emissions at different harmonics frequencies 4.8GHz, 6.2GHz... etc, these emissions are regulated and you if you emit more than what the norm says your device won't be compliant. The unwanted emissions depend on how is the layout of the PCB, the SoC, which is the enclosure of the electronics, how the antenna is adapted.

So as a simple rule, place the footprint of the shield and if your are lucky enough and your design pass the test without it, then don't assemble it. It will reduce a lot of time in redesign and reprototyping.