Why is mount.cifs not installed suid by default?

I am using Gentoo, and on my machine at least mount.cifs is not installed suid root by default. In particular, this means that I can't use the user mount option with CIFS shares. I noticed that mount.nfs has suid set. Is there some reason in particular that this is done for CIFS/samba, or is it just Gentoo being overly cautious? If it matters, I am using net-fs/samba and not net-fs/mount-cifs. **More Information:** It seems that historically it was very insecure , however as far back as 2010 the Samba team themselves were happy to reallow suid root access, so is this still an issue? I've tried adding suid to mount.cifs, and it works but I want to get some more information about this if someone is in the know.