As an EE (currently on the NASA JPL review board for Mars Science Laboratory motor controllers) that designs electronics for space applications (where magnetic fields and radiation are rampant) I can safely tell you, that without a doubt, the Pronto will have NO problem with those weak ceramic magnets. So work your mod with impunity.

I have circuits I designed running in close proximity to brushless DC motors with Neodymium magnets that are several thousand gauss each. My wife and I use reject motor magnets on the refrigerator. A 3/4" neo magnet will hold well over a 1/2" of paper. If it attached directly to the refrig, you cannot pull it off. It has to be slid over an edge and pried off.

As for flash memory, it is immune from issues with reasonable magnetic fields. Older "magnetic" ROMs theoretically could be susceptible to a weak magnet.

Getting back to electronics in general, when I was designing military electronics, one had to design with "effective loop area" of circuit traces on PC boards in mind so they would be hard to damage with an EMP or a nuclear event. While there is certainly credence to the statement that magnets in close proximity to circuit card wires will induce a voltage (basic physics), the effect is negligable with the high density PC boards with ground planes that are used today. Furthermore, the magnetic field must be moving. A statically mounted magnet does not meet that criteria.

It would take a magnetic field of immense magnitude to hurt the Pronto.

As a goof, one day a coworker and I tried to break a cellular phone (that he wanted to get rid of) by placing it in a 50 ampere toroidal degaussing coil. The phone bounced around inside the coil all by itself, and got physically warm due to eddy currents, but still worked after several minutes in the field. In case anyone is curious, it was a Motorola.