So, https://certbot.eff.org/docs/install.html states that you should install certbot-auto in /usr/local/bin.
I think this is the wrong location.
As stated in the Linux FHS standard http://refspecs.linuxfoundation.org/FHS_3.0/fhs/ch04s09.html
the /usr/local.bin directory is for local binaries. So scripts and programs local to the system for its users.
The /usr/local/sbin directory is for local system binaries. Since certbot and certbot-auto is not a regular user tool but for root/admin users it seems only logical to place them in /usr/local/sbin.
It also aids a little in the error messages about insecure permissions 9at least when you document the correct right settings).
My 2 cents.