"High leakage" is the norm for most consumer electronic equipment which utilizes any sort of noise/high-frequency suppression on the power leads by means of capacitive/inductive filters. The capacitance shunts the high frequencies to ground very readily. The labeling of such devices as "high leakage" seems fairly new to me, and I've been in electronic design most of my life. Medical equipment requiring high isolation usually utilizes highly insulated (several 1,000 volts) transformers to magnetically couple any required power to the device.
The power strips you have obtained are not unusual or different from any other consumer power strips not so labeled. Provided they are grounded, they will not present any additional hazard or concern. If you do connect them without the ground connected you will be able to measure (with an average volt/ohm meter of about 20,000 ohms per volt, not a "wiggly") about 60 volts AC (1/2 the line voltage) between the power strips (open) ground lead and either the line or neutral feeding it. This is the leakage voltage being divided across the two suppression capacitors and the strip's ground. The current will be VERY low however, as the caps are selected to pass much higher frequencies than 60 cycles. But even at 60 cycles, some small amount will "leak" if there's no load (ground) to drain it off. If you were to complete the circuit from the open ground to earth with your body you might feel it, but it would not likely hurt an average healthy person. On the other hand, if you have a pacemaker, or defibrilator, it would certainly be enough current to set off some serious "bells".
If you look at any old (pre-1960 or so) radio, TV and audio equipment it was common to have quite a bit of capacitance from line to chassis, with a separate screw on the chassis labeled "Ground". Naturally, many people ignored, or mis-wired, the "ground" terminal and were rudely shocked by their error. No pun intended. Hence the advent of three wire cords.
One last word, another device commonly found in these "power strips" are MOVs, "Metal Oxide Varistors". These devices are designed to break down and pass HUGE amounts of energy to ground, or line to neutral, in the event of high voltage surges. Most 120 volt "surge protectors" use MOVs set to conduct around 350 volts. These MOVs can become dangerously leaky if subjected to small surges repeatedly. Such a leaky MOV could hurt you if the power strip were ungrounded. Most of the time the damn things just blowup and short out, and the power strip has to be thrown away.
Personally, I hate the damn things. IMHO if the voltage surge gets to the point where the MOV conducts the damage has, more often than not, been done already and the so called "surge protector" is yet one more device to be replaced. I'm not saying they don't have their place, just not in cheesy AC power strips (unfiltered) plugged into the wall. Since your strips are likely filtered, that's a far better device, but still not quite what they're marketed to be in terms of device protection. Mostly, these filtered power strips are employed to help meet FCC Part 15 regulations on radiated electronic interference.
They would be a nice thing to have on say VF Motor Drives, or brushed universal motors, in your shop if you listen to AM radio, etc.
Guess that's all I can remember, hope that helps satisfy your curiosity.
Mark
