The highly-ranked Delhi Belly question has a number of answers that allege bottled water from minor/unknown brands may be contaminated or otherwise unsafe.
Now I've heard of tap water being sold as spring water (primarily in the West, where tap water is safe to drink anyway). I've also heard of various scams involving refilling empty bottles with sketchy water and reselling them to clueless tourists, with India in particular once being notorious for this, and many guides still instruct you to both buy only double-sealed bottles (plastic & cap) and crush used bottles to avoid this.
However, I've drunk plenty of exceedingly sketchy looking but properly factory-sealed bottles of water (Exhibit A below), and as far as I know I've never gotten sick from one.
So: is properly sealed bottled water ever unsafe? Research and news articles preferred over anecdotes.
Clarification: I'm aware there have been incidents of lead in tap water, bottled water being accidentally contaminated with chemicals, etc. I'm really more interested in cases of people drinking bottled water and igetting immediately violently ill (Delhi belly style), the way you would in many places if you drank tap water contaminated by sewage etc.