Nissan Repair: 99 Nissan Maxima no start, electro magnetic fields, nissan maxima

Question
Just wanted to let you know, the problem I had with my Max was the computer keys.  After I told my dealer what I ad checked, they said it was probably the keys.  I towed it to the dealer, they confirmed it and reprogrammed the keys and all was well.  My question to them was what caused it and could it happen again?  They said possibly a low battery or using a non-programmed key, neither of which it was.  It cranked great, and I have no other keys that will fit in the ignition except the ones that work.  Further than that, they had no idea on why or if it would happen again.  Any ideas on how to prevent this from catching me miles from home instead of conveniently in my driveway as before?

Thanks,
Frank

Answer
Frank, fo you work around coils or magnatrons?  If you are around electro-magnetic fields you could have this as a cause.  I used to work around aircraft and when some systems fired up they would wipe the keys memory out.  That would be my best answer to the question.  Oh, if you are working on cars and get around the coil enough that can cause it too.  Keep a spare programmed key away from any of the aforementioned to keep the problem from happening again.