<BIG SNIP>
I ended up buying the AST-branded ones from an online retailer that shares its name with a large river in South America. They seem to be quite decent. They use 18AWG silly-cone wires and, as Marco Reps would say, "proper" banana plugs. I don't understand why they went for safety plugs since there will never be more than about 1V between them (I measured 0.910 volts while measuring a 20kR). Maybe because a foolish person might measure the resistance of a charged 600V capacitor?
The whole premse with "safety" shroulded 4mm plugs is not just what they are intended to be used for but how they may be misused. This can be deliberate or the resut of a mistake or lack of knowledge. Senario is this: Worker A connects those kelvin clips to mains to measure with a Fluke. Worker B "borrows" the Fluke and leaves connected leads lying around. Worker C (maybe a cleaner or similar non technical person) moves the leads and gets a shock. In a single worker or hobby environment this is less likely but not impossible. As a teenager I got a very bad shock stripping a mains lead because my brother plugged it in while I was looking for a pair of cutters (he says it was a mistake, I'm not so sure).
In theory for work apllications in the UK, apart from leads that have a fully insulated / isolated device attached to one end e.g. power input leads, all 4mm plugs should be shrouded. The only exception to this is if it can be shown that all power sources in the area of use are less than about 50V (extra low voltage). This has actually been the law in the UK since the mid 90's but it is commonly ignored.
When this law came out in the UK, it was made clear that compliance was required "regardless of cost or inconvenience". I was responsible for safety for my employer at the time. The company had literally thousands of 4mm plugs and sockets on test harnessess including some on 200V supplies. My instruction that they all had to be replaced was not well received. The safety role went to a senior manager allon with a letter explainin my take on the subject.. I happened to visit them last year and despite two changes of premises thay still have unshrouded 4mm plugs
Shrouded plugs are even more important in europe where an unshrouded plug fits into the mains outlets.