No need to fear the CRT. The zap from that feels like a strong static electricity shock on a dry winter day. It doesn't feel good and should not be handled carelessly, but it's very unlikely to kill you.
Obviously you've been lucky-CRTs are
known to be lethal under the wrong cirumstances. I would
always discharge it before handling it (use a grounded screwdriver and touch it against the CRT).
Weird that others haven't reported the same thing with Plus or other Compacts. Also defies probability that 7 machines would exhibit the same problem simultaneously.
It is possible that these Pluses have been stored under certain conditions that could cause this. And most likely they could have been stored, or possibly even used (although not as likely), together for a long time, so could all have been under the same circumstances.
