People are creatures of habit. I'd bet that most people have a very small set of websites that they visit on a regular basis. So those people that say it happens "all the time" for them... it's probably that they regular a website with something weird or odd going on... as you suggested.
It is always without fail data-heavy websites such as newspapers and those with lots of photos. Safari gives the 'there was a problem with this webpage so it had to be reloaded' message, and other iPhone browsers simply crash to the home screen.
This issue doesn't occur when browsing the same websites on my Android tablet, or my pc, so it therefore cannot be a problem with the website itself. Also, my father spends hours browsing newspapers on his iPhone 5 running iOS7 and experiences no crashing whatsoever. So whatever the issue it appears to be specific to iOS8.