It depends on the purpose. Posting a 1 star trade by pre-arrangement is one thing, posting it in the general course makes it seem like the player is more interested in benefiting themselves rather than their fellowship/neighborhood.
Of course I meant a standing arrangement.
My first fellowship told me to post a one-star trade and ask in chat or by mail if I needed anything. We had a fair trade policy in general, so we knew if a new player posted one-star it was a request for help even before the mail went around. I posted a couple one-star trades early in the game when I needed help, and accepted my fair share from new members later on.
We had three-star trades but as I mentioned earlier, they were largely an attempt to try to get more dust into the fellowship from neighbors or world trades.
Arbitrage adds fluidity to the market. A and C may not have a feasible trade, but Trader B is holding a large inventory which allows him to sit in the middle and buffer trades for both A and C. Trader B is assuming some risk, after all he's tying up capital and he COULD end up eating a ton of excess goods, so he does need to make a bit of profit on each transaction.
I just realized the fundamental problem. Some players are not viewing the trader as a free market because we can't give goods to friends or fellows. Three-star trades can either be a poor substitute for a gift system or serve the normal free market role. Unfortunately, there is no way to tell the difference. Even if your priority is to be helpful to your neighbors and fellows, sometimes being nice means leaving the three-star trades for someone else, while other times it means accepting as many as you can.
If Fellowship only trades were allowed, I would be blind regarding much of the trading activity in my own neighborhood, and I wouldn't have a clue that there was a major trader on the fringe of my discovered area.
We seem to be anticipating the same outcome, that players would default to restricting trades to their fellowships.
Maybe what we
really need is a way to give goods to other players without involving the trader.