That’s an interesting concept...but I see a few possible flaws with that.
First, that’s what regular players crimes are for. If a player feels like helping their gang [do crimes] does not benefit them then either they are greedy or they are in the wrong gang as it does not cater to its members.
Besides not that that’s the case with territory wars gone but what about players who don’t wanna level? That would force them not to help the gang crime which is the original purpose of gang crimes.
Maybe find an alternative way of rewarding players? Like have achievements/medals for how many gang crimes a member participated in? But that could be easily abused as well with 1 or 2 members crimes. Then again your gang would get pissed off if you’re there wasting crimes so that could be fun.