It means they're a bucketshop and on the other side of your trades, they hedge aggregate above a prescribed risk threshold as opposed to hedging individual trades. That's not a problem in itself but for a shop like FXCM who have very little integrity and seeing as they have a vested interest in seeing you lose they are quite prepared to take advantage without any hesitation. In other words they hold all the aces and will deal you whatever cards will be the most profitable for them, usually at your expense
Ha - did you used to work on their dealing desk and have first hand experience of how they rip off clients on an individual basis??