I find it unfathomable that some travelers just think they can buy a ticket and just fly to a destination. I suppose some first-world travelers are just so privileged that they don't need to worry about documentation that they need to procure before heading out. I guess they just think that all they need is a passport and a ticket, and they can board that plane to a foreign country. As someone who holds a passport from a third-world country, I find that bizarre.
So when they realize that they need to have documentation before they can enter a country, they panic. "Oh, I didn't realize I need a visa to go to Russia!" "Oh I didn't realize I can only stay in France for 90 days!"
The thing I find surprising is that most of these people are Americans, and I am sure they don't expect foreigners to simply show up at American airports and be let in without any documentation whatsoever. Even Europeans who have visa-free entry to the USA need to pre-register in the system before being able to board the flight.
Oh, and one other thing, when they realize that they need a visa, they sometimes ask "How can I get a VISA?" As if this document is an acronym of some sort.
I have a theory. I think because the USA is such a large country, that there's a higher probability that whenever someone travels, it would be domestic, then people really don't know these issues regarding paperwork involved in entering a foreign country. Compare that to Europe, where countries are smaller, and in some places, you won't be able to go driving within a few hours before hitting an international border. So whenever people travel, it is more often the case that people would need some form of official documentation, like a passport and a visa.
So yeah, I can see where the ignorance comes from.