A moderator on the official Midway forums has confirmed that Stranglehold will not be region free for the PS3. This is understandable for the collector's edition, as it also includes a copy of the film Hardboiled on the disc. There are licensing issues that are far more strict and complicated when it comes to movies, rather than games. Which is why Blu-Ray discs aren't region free either.
However, the standard edition, which does not include Hardboiled on the disc, will also be region locked. There is no explanation for this as of yet. This whole issue does bring up an interesting point for discussion, though. With the capacity of Blu-Ray discs allowing for extra content. Would you rather sacrifice the region free nature of games for more movie pack-ins? We expect to hear a resounding "no" from the European gaming community.