Geoff, note that he said "reasonable explanations."
First, as I have explained in detail in various fuse-related threads here, measured differences that have been reported among various fuses are too small to account for the sonic benefits that have been reported.
Second, as I see it the other kinds of explanations that have been proffered by you and others, such as reduced susceptibility to the effects of vibration, reduced susceptibility to RFI/EMI, exposure to what has been misleadingly referred to as "quantum tunneling," etc., are descriptions, not explanations. They describe some of the physical characteristics of the fuse, or how it has been manufactured.
But in the case of a mains fuse, for example, they do not explain how differences in those characteristics relative to say a Littelfuse or a Cooper Bussman fuse would affect the AC in a manner that would improve the sonics of a component, much less the sonics of a wide variety of components that are completely different in design and perform completely different functions. They also do not explain why those differences would not be totally swamped by the corresponding effects of everything else that is in the path, including circuit wiring and wiring in the power transformer, which involve far greater lengths. They also do not explain why in cases where the fuse upgrade does in fact make a difference why that difference is always for the better, regardless of the design of the component, the function of the component, the system it is used in, the AC voltage that is being provided, and regardless of whether the application involves AC or DC currents.
And they certainly don’t begin to address the effects of the fuse in a manner that would provide any kind of quantitative perspective. To clarify what I mean by “quantitative perspective,” in an automobile-related forum no one would assert that the weight of a paper map placed in the glove compartment would dramatically affect the acceleration or the gas mileage of a car, due to the obvious insignificance of its weight, relative to the weight of the car. We all have a quantitative understanding of that. But in audio quantitative matters and matters of degree are less obvious. So as I said in a post in the SR fuse thread:
… audio is somewhat unique in that there are countless technical variables that can be cited for which it is not readily possible to define a quantitative threshold separating what may potentially be audible in some systems from what is unquestionably insignificant. In the absence of that kind of quantitative perspective there is essentially no limit to what a perceived or claimed sonic effect can be attributed to. Or misattributed to.
Consistent with your comment just above, repeating a hundred times that explanations have been offered does not make it so. At least when it comes to "reasonable explanations."
Regards,
-- Al