I discharge the CRT whenever replacing analog boards etc but not once have I ever heard a discharge. I understand it’s just a fail safe in case the bleeder resistor fails (or you’re working on a really old ab without one)
Also I have a capacitor discharger and I’ve never a residual charge on any of the caps on a Mac analog board (that I can remember).
As recommended earlier, when doing upgrades etc I just don’t touch the crt out of caution but I think any risk even if you did touch it (when the machine is off) is very low.
Note I'm only saying don't discharge it because the components they said they are working on can be removed without getting too close to the high voltages. It's not worth taking risks, and only poke at such things when somebody else is about to take you to hospital if something terrible happens.
I'm of the opinion that you are exposing yourself to more danger by discharging when you don't need to. Don't touch the CRT or anything on the analog board, just remove the hard drive / logicboard.
Also keeping it off for a few days beforehand to be extra sure is not a bad idea either.