For shared accounts, it's really annoying if others mess with settings. For that reason, I use the following piece of shell code that I put in .bashrc. Explanation: you configure the MYMACHINE variable as the IP address you usually come from.

  # If we're logging in through SSH, write this down
  if [ -n "$SSH_CLIENT" ]; then
    # Alternative settings
    MYMACHINE="172.16.140.14"
    FROM=`echo $SSH_CLIENT | cut -f1 -d" "`
    case $FROM in
      *$MYMACHINE)
        export TMOUT=180 #Logout after 3 minutes
        set -o vi
        # all sorts of other settings
      ;;
    esac
  fi

Yep. I spend all day connected to machines that I have to access through a jump server because they have no direct internet access in or out themselves. No way is it worth it for me to customize anything there.

I realize that this is a pretty rare situation though.