Depends on state regs what goes or doesn't go over the vent. Some forbid it, some don't care. I find that a vent guard is less of a fire hazard than 2 pounds of pine needles stuffed into the vent by a starling, so I can't imagine any state regulator with 1/2 a brain forbidding the installation of a vent guard. Have pics of pine straw nests IN the dryer, for the day my state decides to try instituting a stupid "no vent guard" rule here.
Kevin, I think you were in the Navy,...so you understand the irony in "government logic".