With current server population it is too optimistic to expect peope to join and be active in your faction. Unless you offer regular PvP that is. Police factions are overall not attractive nowadays as there is little to do as a police member. There are not that many traders to inspect, and even if you do inspect them - they are just legally passing by, no smugglers (as smuggling is not profitable enough to rival ore trade), no piracy because of little number of traders, and no organised unlawful raids. This all is not because of inactivity and bad gameplay of factions, but because of the sheer server population. And the remaining population is just more invested in some other factions/RP that do not do illegal activities in areas where police can interact with them.
You did good job as KSP, but looking at all Houses, perhaps, only Liberty has activity for police faction. BPA is dead, Rheinland Police is dead. Gallia police is trying really hard, kudos to them for this, but with current Gallic legislation it is unlikely traders will go into Gallia, and indie miners unlikely will be mining there.
I should note, however, that being only 2 or 3 members in a faction is not an obstacle to continuing playing it, as long as you enjoy the process. 3 are required for offdom, but applicaiton for offdom now takes 6 months which is ridiculously too long and simply not worth it given the benefits you can get as OF.
Good luck with your further playing on Disco, you you decide to stay that is.
