"In addition, to deny a proposal on the 'possibility' of something coming up is a big step down the slippery slope of guilt by association."
NO!!! GSA has a published, well-known position that creationism is NOT SCIENCE. Austin has a 30 year track record of creationist pseudo-geological research. Guilt by association? Give me a break.
And don't bother me with blather about not infringing on Austin's freedom of speech. GSA is a corporation, not the government, and can bloody well regulate speech as it wishes. Indeed, this is what GSA does every day: it's called "editorial decision-making".
GSA just gave creation "science" its imprimatur and violated its own published position.
While I can't speak for GSA, I can see reasons for rejecting or accepting the MSH field trip proposal. One the one hand, there is the point that "devilcat" brings up - there is no reason, based on past history, that Austin is doing anything but creation flood-geology. And if that is the "paradigm" that Austin is using to inform his statements on the field trip, then that is clearly not science. And my experiences on that trip have only supported that thought. There was no real science on that field trip.
The other point to consider is that, as members of GSA, they are entitled to the opportunity to share ideas (anyone can submit a paper for publication, but it must pass muster before being published). Are field trips subjected to the same level of peer-review as research papers? What if the field trip was proposed by an "Expanding-Earth" proponent? Would their personal feelings about how MSH might inform us about the relative inequities in sea-floor spreading versus subduction render the field trip void? If the earth expansionists laid out a field trip proposal that discussed factual information, and did not advance any particular interpretation, would that field trip be okay?
There was no science brought to the trip by our guides, but the statements made were at least an attempt by the guides to pose their ideas in a non-creationist framework. While it made for weak science, it at least allowed for everyone on the trip to get something constructive from the trip. Did the trip provide some additional "street cred" for flood-geology? Yes, almost certainly. Would denying the trip have opened the door for legal action? Doubtful, since, as "devilcat" said, GSA is not the federal government and does have some editorial control. Would Austin's first-amendment rights have been violated if the trip were cancelled - no, likely not. But, as I understand it, the actual field trip proposal made no mention of creationism or other anti-science goals. And although I do not know the nature of the exchange, I do know that there was an email discussion between Austin and people at GSA.
Ultimately, the trip happened. The benefit to Austin was, at a minimum, a field trip guide publication, at least tacit support for his work by GSA (at least that is how it will be billed), and a training tour for a handful of other creationist flood-geologists. Those of us that do real science got to see a unique section of the debris field, a volcano, some western toads, and we all received a rather nice 60" panoramic photo of the mountain and spirit lake. One more thing that I received was an opportunity to learn about what the young-Earth movement is up to and new ideas on how to teach deep time and evolution in my classes. These classes are taken by education majors, so I end up reaching over a hundred future teachers each year. The better able these students are at discerning real science from cargo-cult science, the better we'll all be.
So that brings me back to my title. Who was being ethical here? Did Austin violate the ethics he's agreed to when he became a member of GSA? Well, from a legal standpoint, I don't think he did as far as the field trip is concerned. Did GSA? Again, from a legal standpoint, I don't think they did when they accepted this field trip proposal. Does the whole thing leave a bad taste in my mouth? Yes, it does. But, the law of unintended consequences can be tricky. I don't think anyone, myself included, would have realized how much science education fodder this trip has provided.