Duplicating Arguments in CF9

In cf7 and cf8 if you do the following:-

<cffunction name="duplicateIssue" access="public" output="false" returntype="void" hint="">
        <cfargument name="arg1" type="string" required="true" hint="">
        <cfargument name="arg2" type="string" required="true" hint="">
        <cfargument name="arg3" type="string" required="true" hint="">
        <cfset var local            = duplicate(arguments)>
        <cfset var local2            = duplicate(arguments)>
        <cfdump var="#local#">
        <cfdump var="#local2#">
        <cfabort>
</cffunction>

<cfset duplicateIssue()>

They will output the same. However, in CF9 the first assignment to local is ignored and the local scope is populated. This means that the current application I work on cannot be migrated to CF9, as there are lots of occurances where the arguments scope is being duplicated into a struct called local. I know why this was added in CF9 to make life apprently easier for people who don't like varring things but it has changed the behaviour quite drastically and will take a lot of chages and testing for me to upgrade.

Any advice would be greatly appreciated,

Simon