[AnypecekceS]

Fine, whatever, you aren't supposed to respond to post edits by the way . Even though you did you still have not answered this question, which I am going to pose as straigthforward as I can:

Since all that prevents an LCD or LED backlit screen from tanning the skin of its users is a filter, what is to stop monitor manufacturers from shipping their screens without this filter? Presumably manufacturers do not want to maliciously tan their customers, but some might forget to install the filter. But this has never happened, why? What is more, some manufacturers it seems have profit incentive to not place the filter and in fact market a computer screen that also tans users, though it is not clear what government regulations are on this topic. Is this reasoning wrong and if so how and why?

First: It's fluorescent lights that emit UV rays, not LEDs. Second, fluorescent light filters aren't filters per say. The lightbulb itself is coated on the inside with phosphor. Forgetting it would be like forgetting the engine, wheels and doors in a car. It's not like it's some afterthought. It's a fundamental part of the construction of the bulb. Third, the bulb wouldn't emit much visible light if you didn't have the phosphor coating. The actual bulb emits UV rays and the phosphor coating absorbs them and then emits visible light. This is the same way a CRT monitor works, only the phosphor is absorbing electrons in a CRT. The UV rays are not visible to the human eye. If it didn't have the phosphor, you wouldn't see anything.