bind-tty-special-chars (On)
If set to On, readline attempts to bind the control characters treated
specially by the kernel's terminal driver to their readline equivalents.
Disabling it doesn't actually stop readline from binding those control characters. It just enables you to override those default readline binds. If the variable is set to On (the default), that's not possible.
Also, another thing I have noticed, is that I cannot catch the SIGTSTP (Control-Z) signal with the `trap` command. I can catch other standard signals, e.g. SIGINT (Control-C), but not SIGTSTP (along with SIGSTOP and SIGKILL, obviously).
The readline man page is a little misleading:
Disabling it doesn't actually stop readline from binding those control characters. It just enables you to override those default readline binds. If the variable is set to On (the default), that's not possible.