Wow, if the magnet is tripping the phone's mode it means the produced field is strong enough to mess with the data on the magnetic strip of your Credit Cards, Point of Sale and EFTPOS cards. I would be careful where you lay your wallet that holds all those cards!
It was just before Christmas last, that my local convenience store handed out cute refrigerator magnets the size and shape of a CC that had the store's contact details plus a neat picture. They even handed the magnetic card back to you with your EFTPOS card and many people just put them together into their wallets. I was concerned the minute I saw the things and sure enough the card was dead but I'd time to have it fixed before the week where businesses and banks close over Christmas. Lots of people were not so lucky and you can imagine the trouble not being able to access $ especially at that time.
So I always keep magnetic devices no matter how 'weak' well away from my mission critical banking needs. Even the mag catch on my iPad's leather case concerns me.
