After it's been turned off and unplugged?

Well, I got zapped from the 2nd anode of a B/W tube after it sat out of the set for a few days. The best thing to do is discharge it to chassis ground using a HV meter and probe. You can also use a 10 megohm resistor to discharge it. BE CAREFULL!

And also make sure to discharge the electrolytic caps in the power supply. These can hold a nasty charge for long periods of time, either due to the design of the circuitry or a fault in the set. Don't ask how I know...

Bigger tubes hold charge for a long time and can redevelop charge after sitting unused for a while.

When i was in the GE set working yesterday, I was pulling the cup off the 11sp22 carelessly when removing for a cleaning. Got a jolt, but on that set the HV isn't enough to kill or really hurt. Not recommended but I get stupid at times.

Not only can the CRT hold a charge for days or longer, but they can actually recharge after being grounded out. It happens a lot, particularly in larger later-model color tubes. I always just left a cliplead from the anode to the dag ground strap to be sure. But no matter what, it can't hurt you unless maybe you have a heart problem etc. It's just static electricity like you get from running on carpet and touching a door knob. (that is; after the TV is off). Naturally, if you get zapped, the shock can cause you to smash your elbow, or drop the tube, etc etc. So take all this in context!

Charles

Also the charge can come back through the HV rectifier tube...a long time ago I pulled the plate cap off a 3A3 (set unplugged) and went to remove it without discharging the CRT and got shocked when I touched the 3A3 plate cap.
I have noted the re-accumulation of the charge on color CRT's too.