Recent versions of bash can also be compiled with syslog support by
defining SYSLOG_HISTORY but if your users are hooked on tcsh that
probably won't help (I don't think it's enabled in the Fedora builds
anyway).
And any remotely malicious intending user will simply go into vi, set the
vi shell and run commands untraceably while editing.
If you need to do auditing then you need to use the auditing tools.
Better yet don't allow people you don't trust near the machine ;-)
Also as you are in the civilised part of the planet, don't forget data
protection and privacy law !
Alan