[lbriner]

You could also say that since the maintainers are doing this for free, it is OK that some of them work for businesses that provide (optional) technical support.

However you mileage might vary. We found someone listed as a postgres consultant to help us but aside from a load of (alleged) personal problems that made the job take ages, I realised that the optimisation he sent me was basically a rehashed version of something I found on the internet, which he was obviously misrepresenting as his work. He got really arsey with me when I told him that I was really disappointed with his service!