I may be one of these people. At least for the more obscure places, the highway pullouts and national forests and things, if I see another person parked there, I’ll typically park next to them. Safety in numbers, the more people parked in a turnout, the more legitimate it looks to park there
Don’t forget that these restrictions also apply to the Americans living in Guam, American Samoa, and the US Virgin Islands, as they all have the same status as Puerto Rico. It’s interesting too because citizens of the 50 states can vote absentee from other countries, and American Astronauts have voted from space. That would make Puerto Rico, Guam, US Virgin Islands, and American Samoa the only places in the universe an American can’t vote for President
Not very up on biology, so not sure if this would even be a thing, but I would say some kind of internal structure like plants allowing animals to overcome the square-cube law