How important is the EMI protection from an I/O shield on a motherboard?

[I put forks in outlets]

I have recently built a computer for a friend, and forgot his I/O plate. I understand it protects from EMI, dust, and other minuscule things. Another friend who is taking a CIS class swears up and down that it is literally the equivalent of life or death and shorting is so unbelievably common that I am completely dumb for forgetting such an important piece of hardware. Now here is the question: Am I really an idiot and should I desperately rip his computer apart to insert this I/O plate, or is it not a big deal. The only reason I don't care is due to the fact I have built computers for ten years and never heard of a short do to lack of an I/O plate. And I know for a fact that brand machines only have them to pass FDA.

 

[Darkbreeze]

The I/O plate SHOULD be installed. Period.

However, I've build, run and worked on many tens of units that had no I/O shield, and there are plenty of open air cases that don't incorporate them at all. None of them ever had a problem due to a lack of the shield and nobody ever dropped dead because it wasn't there. In fact, I have an ASRock AM3+ board running my old FX 6350 in the garage being used strictly as a media machine, right next to a Core2duo I use for my automotive applications, and neither of them have I/O shields because they were lost sometime prior to my ownership of those motherboards and the manufacturers no longer have them available.

They've been that way for at least two years and are in a very rough environment where I'm constantly grinding, blowing, spraying and otherwise polluting the air in my shop with all manner of contaminants.

If and when you can take the time to install it, it would be a good idea, but it's not the end of the world without it. Make a plan to get it installed when it's possible though as it does help keep things from getting where they don't belong and also helps to strengthen the ports it attaches to so they are less prone to damage.

More important is the question, "Why do you put forks in outlets"? That's a much worse idea than not using an I/O shield. By the way, don't put any forks where the I/O shield belongs, that's a bad idea too.