Solaris 11 Security Benchmarks

Began doing some preliminary security benchmarking on a fresh install of Solaris 11 and the immediate thing that jumped out at me was that system accounts default shell is left blank in /etc/passwd (no surprise there). But what is surprising to (to me anyway) is that /dev/null is no longer considered a valid shell. Is there a reasonable alternative to using /dev/null as default shell for system accounts?