I don't trust an open source solution by a major player unless it's published with other major players. Otherwise, the perverse incentives are too great.
Changing license terms, aggressive changes to the API to disallow competition, horrendous user experience that requires a support contract. I really don't think there's a limit to what I've seen other companies do. I generally trust libraries that competitors are maintaining jointly since there is an incentive toward not undercutting anyone.
