I got a call like this just today, saying that they were a law firm working on legal action against MVC. The woman asked if we were aware that MVC had been taking owner inventory and renting it out on sites like Expedia and Travelocity for up to 50% less than what owners were paying in maintenance fees. But she was calling for my mom (who recently passed away) and I told her that she no longer owned any Marriott timeshares, and so she said she take her out of their system so we weren't bothered again.
I don't know if it is legit or not but she seemed a little too polite and professional to be a scammer, there was no pressure to do anything. But maybe I didn't let her get that far.