Electromagnetic interference

My new desktop cnc router/mill/engraver came with the warning in chinglais "there should not have the magnetic interference within 10 meters". This is generally easy to adhere to - except that wireless boards and wireless dongles in/on a PC emit EM radiation and PCs tend to be closer than 10 metres from the cnc machine - mine is right alongside (30cm). So has anybody had trouble with electromagnetic interference from PC wireless devices or is the strength just too low to have an effect. If there is a problem - then I can just disconnect the wireless - but its useful to keep it otherwise.