Have you ever gotten into work forty minutes late and explained to your boss that 'no, really, I didn't sleep in—the F train just decided to stop between York and East Broadway for a twenty-minute power nap and there was nothing I could do?' And then did your boss pull up mta.info, click on the F icon and say 'well, the MTA doesn't say anything is wrong with the F—do it again and we're going to have to seriously talk about your punctuality.' Yeah? Well, we have news for you!
Previously, getting the MTA to prove you weren't a liar could be a hassle, as the MTA's alerts were an ephemeral thing that could appear and disappear from the interwebs like the subway-hopping ghosts in Ghost. But not anymore! If the MTA put out an alert at some point about your troubles (a big if, we know), it is now archived on their website for you. And those archives go back to October 2008!
Of course, this also now makes it harder to bend the truth when you did, in fact, sleep in. But that is progress for you.