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.