[skates]

Tell the student, not the professor. I am a math student, and in almost all of my courses, you can find partial or complete solutions for many of the problems online. The deal is that if you tell the student he can't copy, he probably will still keep referencing the solutions, but will start to do stupid stuff like changing the variable names and changing the wording. As far as I'm concerned, this is okay, since it at least means that the student is thinking about the problem and there really is no way to prevent someone from referencing solutions. Also, to think that a sophomore/junior engineering student can always come up with alternate ways of solving something is ridiculous. Sure, there are intuitive and creative solutions for many problems out there, but most of the time the solutions you can find online are the simplest and are less involved.