Probably far more effective as a teaching moment with the poor guy being shocked than without!
I remember building two Heathkit color TVs and the cautions in the assembly manuals about the charge that the picture tube could hold from the factory test routines, and even after the completed set had been turned off for a long time. As I recall the voltage was around 25K and probably many microfarads.
And yes, both sets worked perfectly and for a long time. "Alas, poor Heathkit! We knew you well." (with apologies to Shakespeare)