I just received the Travelon convertible backpack from QVC (has a large metal ring at the top). I ordered it Sunday and for $4 extra got the expedited shipping. It was due to be delivered on Wed, but came Tues. I bought it for our WDW trip in 9 days so I haven't used it yet.
I was worried about the magnet too. Your credit cards, etc go into a large zippered pocket on the back of the bag (there are slots for pens, cards, and a mesh zippered pocket for loose items). Then on each side (the middle section of the bag) there is a zippered pocket (will carry my large camera in here). Next is another small pocket (has a little velcro pocket inside for a cell phone). This is the pocket that has a magnetic closure ( I wonder if you could demagnetize it just to be safe). I wouldnt keep anything valuable in here as someone could easily grab it. Finally there is another larger pocket on the front which is zippered. I plan to carry some snacks, and other kid stuff in it.
I was worried the bag wouldnt be big enough, but I almost wish it was a tad smaller. I do like it though. One zip of the strap converts it from a shoulder bag to a backpack. The true test is coming!
alison