I always hate to have to report security breaches within the genealogy community, but GEDmatch not only experienced a breach over the weekend, they are still down while the situation is under investigation.
In a nutshell, for about 3 hours on Sunday, July 19th, all of the accounts, including law enforcement kits, were available in match lists for everyone. Also, kits that had been opted out of law enforcement matching were apparently, based on screen shots of their security settings taken by users who signed on during that time, also available to law enforcement in match lists.
Here are the three announcements on their Facebook page in order of posting.
The first one was posted on July 19 at 6:09 PM.