For transportation, the best way to get those rules across so players know is at the point of sale, through the waiver we discussed. I think education is probably the best approach to making sure people know that.
I agree that the two-tier system that is used in the United Kingdom is probably the best approach to ensuring there's still regulation after sale. Basically, that concept ensures that only people who are dedicated to the sport are able to purchase the normal airsoft equipment we see now. People who aren't dedicated—maybe just the casual user—are basically limited to purchasing very brightly coloured ones. As evidence that they're not real airsoft guns, that's usually a very bright colour covering about 50% of the surface area.