ColdFusion MX doet echt wel rare dingen met scopes:

In this release, within a component <cfset x = 1> puts x in the Variables scope local to the component and <cfset variables.x = 1> puts x in the Variables scope of the calling page.

Once this bug is fixed, both <cfset x = 1> and <cfset variables.x = 1> will do exactly the same thing and put x in the Variables scope local to the component.

Until this bug is fixed, avoid using <cfset variables.x = 1>, as this would conflict with <cfset x = n> in the calling page.