I have tried a rare earth neodymium magnet around my Iphone 3GS and the only thing I can see that it affects is the compass.... It has no affect on the orientation change, or anything. Although I did read somewhere that people think it had an affect on there battery charge.. I am not sure about this or not...
A strong magnet will damage the compass only
It will not damage the compass, only make it very inaccurate.
.......a.k.a. damaging the compass? lol.
Or do you mean only when the magnet is present and not afterward.