Factional warfare in EVE Online, by design, ensures that ships of a much greater ship class cannot engage smaller ships in certain deadspace mission pockets. If you and your fellow militia pilots are in a zone designated for nothing larger than frigates, for instance, you shouldn't find yourself getting locked by battleships fighting for your rival militia. Apparently this has started to occur; some players have found that the jump gates to these zones don't actually prevent them from warping in ships of a magnitude not allowed in such areas.
GM Grimmi had this to say at the EVE Online site: "Flying bigger class ships than allowed by the jump gates to Factional Warfare complexes has been classed as an exploit. If you are found doing this we will be forced to take in-game actions as abusing game mechanics is not allowed." So there you go. You might still be able to get in there with something obscenely overpowered and pop frigates like balloons, but you'll say goodbye to your account over it.