So, in the middle of Strat v.2 there was exploit, used by FCC against Mercs. They transferred a lot of useless weapons and armor to mercs, which made it difficult to choose right equipment in the battle. After that, was added limitation of transfers, to transfer something to member of different faction, at first, receiver should allow thansfer. But there are still free transfers inside your faction.
So, you can apply to join faction, then transfer what you want without any permissions and just leave this faction. I tested it both with troops and items.
P.S: DRZ, give me back my troops and horse