Leaks can still occur, but it is such a low percentage that meanmachine1 is correct; you'd likely encounter something else going wrong instead. Still, forcefully bending tubing can cause cracks, so it can be a possibility, and usually user-error, not manufacturing.
I don't understand all the fears about AIOs, but people 'still want to get one'.
Why is there 'fear' in the first place?
How valid is this claim? (heard from buddy, found on internet)
If you're that afraid, why not just get a good air cooler? It might actually perform just as well, or better than an AIO? This seems like the far more sensible solution?
Everyone focuses on forum threads where 'disaster leaks' happen for AIOs. Do some quick math to realize that the insanely small % of people using AIOs have issues...but you'll always find problems with AIOs if you are going to just 'Google for AIO leaks' - you get exactly what you are looking for.
It's like being a firefighter and proclaiming "everyone's house burns down...that's all I see everyday". Your perspective is skewed simply from your narrow vision and finding exactly for what you search for.