Don't require that the samba shares group has "samba" in it
In principle this group could have any name at all. On some distros it's "sambashare" but on others I'm familiar with, it's "usershare". Checking to make sure that the group name isn't "root" is sensible, but beyond that, we don't gain anything by being picky about this, and instead just have the potential to add roadblocks to the initial setup. Let's not.