Having been following this whole thread, I've been thinking mostly about a point that has started to come up in many people's posts in the last couple pages: the difference between calling something "a sin" and calling it "unwise." Some (such as Rich and David) have made the point that the two accusations can be identical. Others (such as Anthony) have responded that they are necessarily different.
I would argue that either one can be the case, completely depending on the context and heart of the person making the observations, particularly regarding how that person views and thinks of the people they are observing. Obviously there is a sense in which a Christian can suggest that something is often unwise without unbiblically forbidding it as sin (like Paul did, as mentioned earlier). But at the same time, it is very possible for me to call a practice unwise and ultimately be making the sin accusation at the heart of the matter.
It ultimately depends on the spirit in which I'm making the "unwise" observation, and how I view those people who partake in the supposedly unwise practice. It would be very easy for me to say, "No, I'm not saying it's a sin. I'm not even saying
everyone would be unwise for doing it. I'm just making a general observation." But if I really look down on people for partaking in the practice, be it ever so subtle or vague, I might as well be calling it a sin, or universalizing the "unwise" accusation. And since so much of true meaning of the "unwise" observation can be revealed by observing how I view those who partake in the practice, and since it can be so subtle, non-explicit and vague, it can often be so easy to miss the condescending or sin-implying side of such an observation.
bwsmith, in reading this thread, I have to say I have honestly gotten the impression that your observations of the "unwise" nature of alcohol partaking have the disapproval element attached to them. If that is not the case, please say so and forgive me for misunderstanding you that way. But if you honestly look down on people who partake in that activity you view as unwise, regardless of how subtle it is, then there is more going on than an innocent, no-sin-accusations observation. I hate motorcycles. I think it is unwise to drive them because of the greatly increased risk of injury and fatality they give to the driver on the road. But I have to continually remind myself that even without directly calling it a sin, if I even do so much as look down on people for driving them (which I have done many times), then I am in fact sinning by going beyond God's Law in my own judgment of people, and I ultimately might as well be accusing them of sin.
When we were discussing the Reformed teachings on Christian liberty, a relative of mine once asked me if I would view him as unbiblically judging people if he had concern in his heart for them and their well-being after seeing a liquor cabinet in their house. I said, "Not at all. But I
would view you as unbiblically judging them if you later found out that it did not in fact create a problem in their lives, yet you still looked down on them in any way for having it, or even implicitly had further notions of disapproval." So bwsmith, I would encourage you to examine your heart toward people who still choose to partake of alcohol in moderation, and honestly answer the question of whether or not you look down on them with disapproval in your heart. Because that will ultimately be the interpreter of what you mean by saying it is "unwise," and whether that observation is a healthy one in the spirit of Paul on marriage and sex, or an unhealthy one that has subtle elements of unbiblical sin accusation in it.