With respect to making the source available, the consequences depend on the target market and the price. For a multi-thousand-dollar product aimed at STEM professionals, yeah, people will bother to recompile without the offending bits. For a mass-market app priced at $0.99 no one will bother.
But I agree that some plugin API looks like the most natural way to proceed.
If it's worth saying, but not worth its own post, then it goes here.
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