Reminds me of the Hand Maids Tale, where the main
character, Offred, discovers that things have changed when the bank machine doesnt work.
All female owned banking had been frozen...
http://en.wikipedia.org/wiki/The_Handmaid's_Tale

Did they have to evacuate Denmark?

I think the point is that the saunas in Sweden are Naked...or is that the sauna users?

The speed of the motor is not important. Its power consumption is. I bet that motor is drawing more power when the magnet is there.

The magnet is interfering with the rotating
field of the motor which accounts for the
change of motor speed. Possibly loading the
motor will return it to a normal near
synchronous speed.

Anyone with a kill-a-watt, a sacrificable vacuum cleaner, a big rare earth magnet and a stroboscope can probably verify this.