That happens already:
$ cat .emacs
(yes-or-no-p "Question?")
$ emacs --daemon< /dev/null
emacs --daemon< /dev/null
("emacs")
Question?(yes or no) Warning (initialization): An error occurred while loading
`/home/dann/.emacs':
error: Error reading from stdin
To ensure normal operation, you should investigate and remove the
cause of the error in your initialization file. Start Emacs with
the `--debug-init' option to view a complete error backtrace.
Starting Emacs daemon.
I suspect that the tool he uses to start emacs provides some bogus
stdin and emacs dutifully waits for input from there.