Here is my original take on this. I think the magazine did the right thing in retracting the original article, including adding an explanation. However, I have to note this from the story:
The reporter had tried to contact numerous outside researchers, including those on the MER rover mission, for their analysis of the claim, but his calls were not immediately returned.
I would suggest, then, that if not enough solid sources were able to be contacted, the story wait a while to get those analyses before being published. Remember, the claim that extant liquid water exists on the surface of Mars would be huge news, so all due diligence must be observed before publishing! That might save everyone some trouble and embarrassment.