Running a Vacuum Cleaner near Tubes

I've been contemplating on asking this question, because I know what type of, highly potential, remarks this question will ensue, but here it is anyways.  Curiosity can, only, be cured by asking or doing, right??

I recall as a kid going to the local drug store, Eckerd Drugs, with my dad, so he could test the Tubes in our T.V.  A few days later, a T.V. repair man showed up at our home and he took a metal circular loop and moved the metal loop around in front of the T.V. screen.  As he did this, the picture on the screen followed the loop.  The guy said, what he was doing was realigning the picture.. AND, to never turn on or off the vacuum machine close to the T.V.

Does anyone know, not think, assume, etc., how turning on/ off a vacuum near tube gear would effect tubes?  Again, this question is, purely, out of curiosity from what I saw and hear the T.V. repair man do and say.  Thanks.