Re: To shield or not to shield, that is the question.
I put a plastic case on my uBitX...but I sprayed the interior surfaces with several coats of a nickel-based RFI insulating spray. It's highly conductive, and I made sure to bond all the surfaces to one another. I do suggest that a thin clear coat be put over it, as the spray can leave some loose particles. Just put painters' tape over the surfaces that need to be exposed conductor for bonding purposes, and clear-coat just enough to keep particles from shaking loose onto the board.
This is the spray I used: https://www.amazon.com/gp/product/B01N3AWGNX
I plan to do some playing with this stuff to see if one can spray an effective antenna conductor onto some sort of substrate. I'm going to try making a small transmitting loop using this stuff and a cardboard TV moving box. The box is in two parts that slide one inside the other, and am going to try using overlapping sprayed conductor surfaces to create a capacitor to tune the big loop, and put another small box with its own loop of conductor (maybe adhesive copper foil) to couple the rig to the loop. Since you can spray as wide a strip of this stuff as you want, it may be possible to get good efficiency and a wide bandwidth with it. We'll see.
It's been my experience that the spray does work to help keep RFI at bay.