Why are some terminal control characters shadowed by readline

stty -a shows cchars: stop = ^S, reprint = ^R. Ctrl-r is shadowed by readline's reverse-search-history, so when I press it I get the readline function Ctrl-s is not shadowed by readline's forward-search-history, so when I press it I stop the running process (eg. sleep 5 ) So why are some cchars shadowed by readline, and some not. How can I make sure all cchars are respected, and still have readline features available (i.e. using bash --noediting is not an option, though it does allow reprint to work).