How disable "Launch File" warning?

When my readers of my PDFs click on an icon to open a video clip (in a floating window, if that matters), they will see a security warning. In Reader - though not in the main Acrobat app - the error message has checkbox saying 'Do not show  this message again', which is great for me since my PDFs (and there are many) can contain 100 or so tiny videos each. Unfortunately, this choice is not remembered when re-opening the PDF - one has to check the 'Do not show this message again' all over again. In a prior version of Reader, one could turn off the launch warning permanently for a particular PDF by going to 'Edit > Preferences > Security (Enhanced) and un-checking 'Enable Protected Mode at Startup'. But this no longer works in my latest version of Reader, which calls itself 2002.003.20314.

I should mention that these videos are linked initially in Microsoft Word, and get transported over to the PDF that Word creates. Linking them from within the PDF itself is more time-consuming (multiple dialogs to go through), and the resulting videos have no buttons to replay them, nor in fact any controls at all.