I produced a night light that came directly off the power line. Some thing like what you pointed to. We had to double insulate the cover. The clear lens for the LEDs was a great problem to design. We had to pass the drop ball test (bowling ball drop on product). There could not be any hole in the case. There could not be a "input or output jack" like an audio amplifier. It is very hard to design a non isolated product. Even a on/off switch needs to be double insulated. I use a plastic rod to reach the switch, in other designs. It took us a year longer than it should to get through UL.
The safety of opening up the case....is not the problem. The safety issue is just touching the output jack. You need to prove to an UL engineer that the jack is at ground (green wire ground) even under a worst case fault. (if not at ground with in 42 volts)