Electrical interference from a cell tower or other transmitting device also seems to cause the MSP to wig out at times. There's a very specific spot where it happens near my home - on one side is a large cell tower, on the opposite (about 1/4 mile away) is another huge radio/cell tower, and in the middle of the turn where the MSP freaks out is an old iron fence. I think the fence is acting like some mega antenna/concentrator and inducing signal voltages in the MSP system. It isn't as far fetched as you'd think. I used to do startups on manufacturing plants, and keying a walkie-talkie would in some cases freak out the instrumentation/sensor measurements.