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The Enhance thin lines feature is an option of the viewer, in this case Acrobat or Reader. It is not an attribute of the PDF file itself (i.e., it is not something defined within the PDF specification and stored in the PDF file). As such, there is no way to assure that others viewing your PDF file don't have this “feature” enabled on their system. (Note that Adobe's mobile PDF readers for iOS and Android as well as most other PDF viewers on other platforms don't even have such an option!)
The feature was designed to deal with the lower resolution CRT monitors of yore (can you say VGA 640x480?). I would generally agree that this option has outlived its usefulness. I have it disabled on all my computer systems here at Adobe. I'll try to recommend that it be defaulted off for future new installations.