Knowing of my interest in oddball warning labels, reader Clark S. alerts me to this $4.95 paperback copy of the U.S. Constitution, Declaration of Independence, and Articles of Confederation, which contains the following advisory (readers may need to scroll to the "Copyright" section, depending on how the page displays)
© Wilder Publications 2008
This book is a product of its time and does not reflect the same values as it would if it were written today. Parents might wish to discuss with their children how views on race, gender, sexuality, ethnicity, and interpersonal relations have changed since this book was written before allowing them to read this classic work.
A bit of Googling revealed that the same publisher slaps the same boilerplate language on other reprints including the Federalist Papers and The Great Heresies by Hilaire Belloc. Do they perhaps put it on all works composed before a certain cut-off date? Wilder Publications is described here as in the business of "publishing print-on-demand books (mostly self-help and public domain reprints)."
I am happy to report that the Cato Institute's excellent pocket copy of the U.S. Constitution daringly omits any warning and lets readers take the Constitution straight up.