When Slack first showed up, their development process seemed pretty fast and loose. There were tons of bugs and everyone who endured their initial forays into 2FA will probably remember the discussions of "Is Slack (the company) responsible enough for people to use the product in a mission critical application?" To be completely fair, they've tightened up their development process significantly and I'm actually pretty impressed that this is the first major gaff I've seen from them in a long time. I'm hoping its an aberration. I'm pretty public in saying that I don't really like SaaS offerings unless I get source code, but I have to use Slack at work, so I'm hoping they are successful ;-)