How do you explain what magnetic fields do to monitors to people wearing bowling shoes?

Techie demoed the effect in about 3 seconds, as On Call again tries to break tech-support world records
On Call The working week sometimes speeds by, sometimes crawls, and often ends with a crash. Each Friday, we try to avert the latter by delivering a new edition of On Call, The Register's reader-contributed tales of handling ridiculous, ribald, and remarkable tech support requests.…