All of the original V is scientifically implausible. I mean, why would the Visitors use human disguises that were so easily ripped away? All it would take is one Visitor falling down and skinning his knees, and whoops, there goes the whole invasion.
The whole concept of the series was to show what would happen if a fascist regime occupied America in this day and age... and it was dressed up as sci-fi to get the NBC execs interested. If you're watching it looking for scientific accuracy you're completely missing the point.