say you had 100 vcc's and used them to signup for promotions, would the biller be able to tell they were all vcc's and smell something fishy? or would it come through like any other 100 cc's?

They could by tracing the BIN (first 4 or 6 digits of a card). Maxmind offers the service. There used to be a large publicly accessible database of BINs around the world.

Here is a list anyway:
http://en.wikipedia.org/wiki/List_of...cation_Numbers

It is of course possible to code a script to flag orders placed using cards with certain BINs.