Yes, you are right. Good catch, I goofed it up.
Thanks for identifying the source and providing the fix.
However, it should also extend the warning message, when -e is honored. You can find a pattern at mediaFolderHidden

If you can update your PR I am happy to merge. If I am asking for too much let me know, then I will fix it by myself.

Oh, whoops. Yep, I'll have that done today.

Looks like it works:

deck@skyscraper:~/code/skyscraper$ ./Skyscraper -f esde -e foo -p snes
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Running Skyscraper v3.17.4 by Lars Muldjord and contributors
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Parameter -e is ignored. Only applicable with frontend attractmode or pegasus.

Awesome. Thanks for the fixes.