Having never participated in a co-op, I'm not sure whether they are managed by sellers or interested buyers, but either way it seems like a money-for-goods exchange? With a direct exchange of money, by definition participants are more like sellers and buyers, or designated agents for sellers and buyers (formally or informally, as it may be). A price is set, or a range, and potential co-op/buyers provide funds for goods. With trading, it seems unlikely that an exchange of plants would occur between a garden grower and a commercial grower or seller. So, selling or co-op buying seems to be much more of an economically regulated and accepted form for exchanging goods for money. That gives control to the sellers, who can wait until funds are provided, but who may or may not deliver "the goods." It can be very difficult for a buyer to recoup those funds if something goes wrong when the transaction is done in an informal selling environment. In that transaction scheme, it makes sense to provide public feedback to protect both buyers and sellers, at least as far as is expected from feedback mechanisms.
In a trade, however, there is less risk of loss of funds other than mailing costs and, in a way, some less risk for the loss of goods, since it is assumed that traders are exchanging excess garden material that would not be sold in any other circumstance. Where that could go wrong, of course, is if one side never sends the agreed upon exchange, or if there are other disappointments that are not anticipated or settled before a trade is complete. For those who are new to it, informal trades can be a great big learning experience (was for me!), so outcomes, even when done in the best of faith, may be less sure or less than what is expected from sellers. My own personal experience has been that trades are completely different than co-op/buys, and involve an entirely different relationship. In my case, I was quite overwhelmingly advantaged by my trader's generosity - and the trade quite literally changed my life in a most profoundly positive way. For anyone, trades can be an equal opportunity for informal gardeners to enhance each other's variety of plants, and perhaps the process could be helped by providing trader's private recommendations for important steps to take, best practices to follow, pitfalls to avoid, and could be developed and contributed to by those who have experience doing trades. Doing an informal, private trade was the best gardening experience I have ever had, and it spurred me on to becoming an even better buyer, hopefully a better and more successfully generous trader in future, and certainly a more educated, dedicated, contented, and grateful gardener.
For those reasons, it makes sense to me that co-op buyers and sellers - anyone exchanging plants for currency - who in effect are sellers and buyers no matter what title they may go by, more understandably need some mechanism for public feedback; the imbalance is wide enough to call for it. Traders, though, working along the lines of re-distributing extra plants (with no intention of selling otherwise) that are then replaced in their own informal gardens by plants or fans kept back, also focus on those extra plants or fans that otherwise might just as well end up in the recycling bin due to any number of garden-based reasons.
With recommendation-based drop-down boxes included in a trade list, offering a way for people to become aware of steps that should be taken and can be supported within the trades list grid, it would seem to me that informal goods-for-goods trades could remain up to traders to navigate with limited risk. Options for drop-down designators might include recording references sought and received through tree-mail, itemizing the equalization of general trade value or tracking agreed-upon trade imbalances if desired, time-allotments for prepping and evaluating plants to be sent, maybe even a section to formally note mutually set limits on the number of items in a first-time trade, especially in cases where traders have not established a relationship of trust or outside recommendations first, etc.
Just some informal thoughts that occurred as I've enjoyed reading about the ways that these seemingly different types of exchanges might be structured to facilitate member interactions. It makes sense to me that money-for-goods, non-negotiated exchanges would be handled in a different way than goods-for-goods, negotiated trades. Especially if there were indications provided through something like a drop-down box for recommended steps to be taken within a trade from ATP lists. If that were the case, responsibility would fall to each party in a trade to ensure their own good results, with the least risk taken. Setting an indelible "rating" on trader's learning curves, non-seller mistakes, unavoidable family or real-life events or delays, etc., seems awkward at best when there is no money being exchanged, and only "extra" materials being made available informally. Wouldn't drop-down boxes, or even a prominent link to advice on steps to take from successful traders, make it more likely that each new trade would be entered into (and conducted) with the intention that, rather than grading performance, traders learn together how to build a relationship for sharing otherwise-to-be-discarded goods? For me, it comes down to commercially sold items being distinct and different than trades of private surplus plants, and I'd love to see the latter remain negotiated in the privacy of informal relationships, perhaps supported by recommended steps which could effectively reduce or negate the need for public feedback.
