I suggest to add new merchant action as alternative to existing "collect from trade" and "transfer trade power" which would allow placement of merchant in the node without collecting or pushing any trade value to downstream nodes. It would serve following purposes:
- getting some profit from end node which is downstream to your home node and you can get trade power there (from provinces, ships, transfers from peace treaties, vassals or trade league members) when collecting or moving trade capital to that node would be detrimental;
- inviting new members to trade league if you are merchant republic;
- applying trade policies like "establish communities" or "hostile trading" if you have free merchant or can sacrifice some money to speed up diplomatic work.