> This assumes it's fun.

Not to those who don't exist in such cultures. It's creepy, childish, strange to them. It's not something they see in everyday life, nor would I really want to. There is a reason why cartoons are aimed for younger audiences.

Besides if your webserver is throwing errors, you've configured it incorrectly. Those pages should be branded as the site design with a neat and polite description to what the error is.