I've noticed a number of ads/profiles on AW where the same pics are also on other sites but with different names. They could of course be the same girl's profiles as they all use pseudonyms but a little continuity would be helpful to punters.
Having said that, if girls use different names on different sites and a punter calls them, how often do they forget what name they used?
But you're quite right, even if they aren't scamming it does give that impression.