I think newer figures like Luke, Batman, DX 10 Terminator and a few others have a better chance of being MIB, sealed and brand new as opposed to, say Black suit Spider-Man, Iron Man MK II or the Tracker Predator who have say around.
I'd take the chance. I mean it's not like you won't be able to tell someone took it out or it was on display, everyone here knows what to look for. I'm sure when they put it back in the box, the plastic wrappings aren't exact or packaging parts are missing, etc. Worst case you get a replacement or refund if you're not happy with their "100% new collectible" policy.
I looked through this topic, and it does seem 50/50. Some have gotten displayed, used/opened items, others have gotten brand new figures. I think people have pretty good chance of getting a brand new, sealed, Jack Joker, Bespin Luke, DX 10 T-800, Batman, Batpod, etc.