It would have been an issue for the acquirer before or during acquisition, if it were present at the time, of course. Some, perhaps many, investors into startup

It would have been an issue for the acquirer before or during acquisition, if it were present at the time, of course. Some, perhaps many, investors into startups also insist on liability insurance. But the founders of Heroku have no more liability than the company in control of its assets, which in almost all cases would be some sort of Limited Liability vehicle.