I repaired TV's, monitors and other high voltage electronics for 25 years AFTER I had been trained by private schooling and the military. I've heard many stories of people who lost their lives from voltage not only from monitors, but from cars, appliances and air conditioning systems. Thank goodness I don't have any personal experiences to share... other than all the years I've spent telling other people to "STAY OUT OF THERE!" 
I still repair the occasional flat panel systems too, and those are just as dangerous as the retro tubes. So stay out of there too!!
Plaz
When I was an apprentice elec engineer I was working on a colour monitor (on my own) and got too close to a leaking LOPT transformer - you could smell the ozone and hear a ticking noise, the ticking was high voltage seeping out from near the edge of the transformer to some nearby point, but it was so small an arc I couldnt see it. Anyway, got too close to it - ~25Kv down my arm, likely had a heart attack because whilst I 'fell away' from the point instead of into it, I collapsed on the floor and was in a cold sweat for probably 15 minutes and couldnt even get up off the floor.
That was the day a monitor nearly killed me for my lack of respect of DC high voltages. To this day I stay well away from the internals of a powered up monitor and sweat a little when I am working inside it even when its off. So yes, monitors are dangerous things. Some things are not worth tinkering with unless you know what you are doing - I knew what I was doing (even as an apprentice), but my inexperience meant I didnt expect EHT to be arcing anywhere from what looks like a solid plastic molded LOPT. Voltage finds a way when the conditions are right, that's why a lot of these high voltage boards have cut out gaps in the PCB etc, some times around LOPT.
