For both C# and Go I use editors that understand the language and can rename all references to a variable with one keyboard shortcut. C# has at least 3-4 of these editors available, and Go has at least 2.
I realize that not everyone's preferred editor may support every language yet, but still I think the solution to this problem is probably just having the language designers provide libraries that editors can use for these refactoring features, instead of through specific capitalization conventions.
It doesn't matter when you're making the edit, it matters when you're looking at the diff and skimming through a hundred identical changes for the things that are actually different.
I realize that not everyone's preferred editor may support every language yet, but still I think the solution to this problem is probably just having the language designers provide libraries that editors can use for these refactoring features, instead of through specific capitalization conventions.