Me and my friends did exactly the same when we were 15. One of us added "Hannah screwed her dog" to the Wikipedia article for Paper. I remember being surprised that it lasted for a few weeks.
When the bot doesn't catch those, there's almost always a couple of people looking at every change as they stream by, but that's an uphill battle that mostly catches the obvious bad edits.
The rate of change to recent change reviewers is too high to catch the more sophisticated vandalism as it happens, that's when things start staying up for weeks or months until some random person browsing the page notices, and hopefully fixes it.
Citation needed...