I wouldn’t say it’s really common, but it definitely happens. I’ve run across something very similar personally, with a German colleague who thought his family would be able to visit NYC, the Grand Canyon and Disneyland in three days.*
Many Europeans just don’t know how insanely large the United States is. Many of the EU countries are the size of Montana at the largest and most are much smaller than that. But in the US, Montana is only the fourth largest state by area and is still only 4.7% of the contiguous United States.
So the country is frickin’ huge, y’all. And a lot of Europeans are just not accustomed to thinking on that scale.
*Sure, technically, you could potentially make it to all three in that time. But seeing anything or having any fun? Hell naw.