Pay Attention to Magnet-containing Covers or Case

Hereafter is a report from Jean Michel.

I purchased a brand new iPod nano 3G last week, and already used it intensively with music, video, podcasts...
So, after couple of days, I decided to purchase a protection case for the iPod, and chose a slick and nicely fitting model from "case logic".
But, then I immediately experience freezing problem with the iPod. So, I reinitialize it... but it does not help.
Did I install a corrupted file or performed an incomplete synchronization? So I decide to entirely restore the iPod... but 10 minutes later, the iPod freezes again.
Last trial, I remove the iPod from its case to repeat the last restoration procedure... start playing music... 5 minutes... 10 minutes... it works!!
Then I ask myself? Is the problem linked to the case? There is a magnet to close it? Could it be as simple as that? without the case, the iPod worked over night while installed in the case, it freezes within 2 to 10 minutes...
So, I remove the magnet, install the iPod back in its case, and... it works!

Magnets have never been good friends of consumer electronics, so pay attention of it before purchasing such type of cases.