In kde 3, krunner (equivalent of xfrun) had 2 very cool shortcuts:
#prog launches man-reader on page "prog" (ie konqueror man:/prog)
##prog lanches info reader on page "prog" (ie konqueror info:/prog)
As these shortcuts beginning by '#' cannot be used in command-line i guess the risk of mistakes is rather low
Fixed in git master, man pages are opened in the default terminal emulator.