Wolfeye's comment is instructive, but not fully imformative. He does allude to one of the main qualities of the equipment being discussed; their current handling capability, which is roughly related to the physical size of parts involved. Another quality of interest here is the what some might call the "insulation" value for the parts inside. This also might be thought of as the "physical strength" to resist the voltage or force being applied to the camera flash control circuit from the electronic flash firing circuitry. If you apply sufficient force or voltage, you can "crack" the part. If you have sufficient force and a low impedance source with sufficient capacity to provide the energy or power, you can "crack" the part and displace the little pieces just a little, or a whole bunch depending on how much power (force and energy) you have applied. In terms of what we might see and hear, did it go "pszzt" with a small blue spark or perhaps even a blue flash, or did it go "KA-POW!!" with a great flash, some smoke, and a tingling sensation or numbness in the hand that was holding it?
Want another analogy? Did you tap on it with an 8 ounce ballpeen hammer, or did you smack it with a 10 pound sledge hammer? In both cases, you will break it. In the second case, not only will you break it, you will also smash the pieces.
The warnings about the possible damage to the late model camera flash circuitry are not just idle threats. There is a real danger to the camera where the circuitry inside the camera now merely must meet the ISO standard of being able to work with a flash firing circuit voltage of no more than 24 VDC. (We can talk about how this was interpreted.) The Wien SafeSync device, or equivalent, will move the high voltage insulation requirement for the actual flash circuit switch, from inside your camera out to a device that is much cheaper and easier to replace if required, than it is to have your camera repaired.