I use tmux with iTerm's integration facilities, so when using it remotely I only want it for session persistence. I can set the prefix key to something bizarre that I'm unlikely to use but I could imagine some Emacs package suggesting it by default and being puzzled about why it doesn't work.
I would prefer to unset it (I'll use explicit tmux commands if necessary) and hide the status bar. I can hide the bar with tmux set-option -g status off
but tmux set-option -g prefix
says empty value
and C-b
continues to work.