Although the Graduate Honor Code encourages faculty to place trust in students, reasonable measures should be taken to eliminate a student's ability to cheat.
Some suggestions follow.
Include a statement on your syllabus about compliance with the Graduate Honor Code. The tenets of the Virginia Tech Graduate Honor Code will be strictly enforced in this course, and all assignments shall be shall subject to the stipulations of the Graduate Honor Code. Be clear about what resources students are permitted to use. Consider placing them in writing on the assignment so that there will be no confusion. If you ask students to do extensive writing, remind them about proper citation methods.