IO Shields, how important are they?

[QueBert]

I'm building a computer for a neighbors sister, not new, just something for her to use. I have everything except the IO Shield. Not to worried about the dust factor to do the open space, but is there that much more of a possiblity of some type of short happening? I was never totally sure what these were for, aside from keeping dust out.

 

[mechBgon]

They help contain the EMI generated by all that high-frequency circuitry. Weird TV/radio reception is one possible side effect of it being missing.

 

[VertigoLabs]

possibly could affect the airflow of a computer in a negative manner ++ temps