Seems the big scientific brouhaha at the moment is PLoS’s recent (clarifications to their) policy that data for a paper will be shared. In my field, the answer to the title of this post is, “OF COURSE!”
However, I get that there are different cultures, that vary by field, about what kind of data sharing is expected, and how much credit should be given to those who share data (citation, certainly, but what about authorship?). As has been discussed, there are also “lots” of corner-cases about where and how exactly the policy does or should apply. My guess is that PLoS actually left this intentionally vague, so that Editors can use their judgement (although hopefully they have been trained on what exactly the policy is meant to do; I can’t find the tweet that suggested this).