My two cents...I agree with the others, and I have seen this come up in other places where there seems to be a bias and distrust against students, which is understandable I think, but it raises a few questions when considering such a "policy"...
1) How do you know it's a student asking for a homework assignment? Granted, in some cases, it could be obvious, but some assignments (like a database course) could easily be seen as a real-world problem.
2) If a student is asking for help on a specific problem (very specific), what makes them any different than any of us? They are asking for help on something just like we are. Aren't we just trying to learn too? Solve a problem too? There will always be short-cut takers out there who just copy/paste code and don't take care to learn, but whose to say some pros are any different!!??
3) Can't one argue that if a student is reaching out to the net and using resources like StackOverflow,that they are "acting" as pros? Seems to me that's more real-world than when I was in college and the Internet was just a little toddler.
4) How do you measure intent in these cases?
Again, I agree with the others, a case-by-case assessment is sensible, but it's an interesting question :) Cheers.