Usage will after before

[Twin]

While reading a book, I came across the following sentence:
I'll burn it down before I'll ever sell it.

I've always been taught that a subordinate clause introduced by "before" does not contain "will". The sentence quoted above seems be an exception to the rule. Why does the subordinate clause read "before I'll ever sell it" instead of "before I ever sell it"? Does it have anything to do with the fact that the author of the sentence is actually not going to burn it (= the house) down?

[Yankee]

Hi Twin

Instead of looking at grammar as a collection of absolute "rules", look at it as a collection of general "guidelines". The problem with many grammar "rules" is that they are often overly simplified. They tend to tell you only what is "usually" true, but not what is "always" true.

I'd say the use of "will" introduces a sense of "(un)willingness" -- i.e. I will never be willing to sell it.

Others may have different opinions about this, however.
.
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