I love my Fluke but keep that old analog meter handy.
Flukes have high input impedance so that the meter won't load down the item you are measuring the voltage on. For 99% of the time - this is a good thing. The downside to measuring high voltage with high input impedance meters is you can get phantom readings.
I was checking voltage on the backside of an unloaded 120VAC circuit breaker to see if it was turned on or off. The breaker was actually turned off but the meter kept telling me there was 120VAC on the terminal. The proximity within the breaker between the input and output terminals was close enough that it was inducing a voltage onto the output terminals. And since the Fluke had such high input impedance, it could actually pick up on this induced voltage. Put in an old analog meter (Simpson 260 in my case) - and it reads properly at 0 volts when the breaker is turned off.