It won't make things more dangerous - that's already done by people who can't handle highway speeds in the first place.
It won't hurt gas mileage - these morons that think speed it the only factor clearly don't understand that the way you drive (throttle position esp.) has more to do with it. (Hence that Top Gear with the M3 v. Prius)
While they're discussing laws that other states have left behind years ago, maybe they should focus on the front plate too.
I remember seeing that earlier in the year on another forum. That's just SO wrong; if you have a problem with someone, the most cowardly (and wrong) thing to do is to mess with their car.
Josh, were you one of the guys I met up there at NTR / AutoX?
Regardless, throw out some info about your car (maybe some pics) before the natives eat you alive.
Having driven down there each year around this time (ZdayZ) since 2005, I can tell you that the Subaru would be great on those roads; especially on the Tail.