+=head1 BUGS
+
+(paraphrasing Neil Bowers) We export all functions by default. It would be
+better to let the user decide which functions to import. And validate() is
+a bit of a generic name.
+
+The question is, after almost 2 decades with this interface (inherited from
+the original author, who probably never expected it to live half this long),
+how to change things to behave in a more modern fashion without breaking
+existing code? "use Business::CreditCard <some_minimum_version>" turns it off?
+Explicitly ask to turn it off and list that in the SYNOPSIS?
+