VMware do not run testing centres in their offices - I doubt this would ever happen.
To answer your original question, I used to work for Global Knowledge - I took my VCAP4-DCA in their Wokingham office and didn't have any problems, and colleagues of mine didn't have problems when they did their exams in their London office.
Regardless of where in the world you take the exam you're accessing a lab in the US, and before anyone asks there simply isn't enough scale for VMware to regionalise the labs.