Compiler enhancement (edit 708): when the /P (or -p) switch is used, it is no longer required that function names start with fn'. The main downside of taking advantage of this option is that it could make your source code harder to understand, since it wouldn't be immediately clear whether a subscripted identifier appearing in an expression, e.g.
something = WhatIsThis(idx)
is an array reference or a function reference. The compiler can tell the difference though. The upside is mainly aesthetic, allowing you to syntactically simplify your functions. This could be particularly helpful in cases where you have class-like collections of related functions and procedures. These can now all share a common prefix, allowing you to adopt a simpler but more object-oriented syntax scheme, i.e. object.verb(params).
For example, the SOSLIB now contains a set of application message logging procedures/functions (in sosproc:applog.bsi) which all share the common prefix "AppMesg.", i.e. AppMsg.SetFile(), AppMsg.Info(), etc.