NOT a scam! It's the movie theater arm of MF. This is how they communicate job openings. I got one tonight re: trailer checks at a local theater (well, their idea of "local" isn't the same as mine, but I digress). Criny.com takes you to Certified Field Associates, the movie-theater division of MF. It's definitely legit.
For what it's worth, here was the message once I logged in:
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MFI has trailer checking assignments available at theatres in your area for the new release "Oldboy" which must be completed on WEDNESDAY, November 27th. If you are interested in conducting these trailer checking assignments on WEDNESDAY, please search in your area for project ID XXXXXXXXX (redacted by me). Or, you can search for all available trailer checking assignments by selecting "Theatre Checks" in the dropdown box. Please note that trailer checking assignments are typically added throughout the week, so check back regularly if you are interested in these assignments! Thanks, Market Force