No. Never. I can't think of any situation that would make selling accounts an "okay" thing to do. A lot of people use it as a "shortcut" to the signature campaigns only to end up getting their accounts banned from the said campaigns. There have also been account sales which resulted in scamming. People are buying reputable/trusted accounts (which I heavily doubt were sold by the owners' themselves, more like hacked.) and then scamming people left and right. If there were to be a service that switched hands and its announcement post was written by the service account, I support suchmoon's idea of just locking the old account and the thread, make a new account and clearly state that the service has been sold.

I just hate people who hack accounts, the local forums are riddled with them. I wrote a thread in Turkish (here) about people buying accounts and abusing the system. There was one specific person who was against me and literally told me that I am basically sucking Veleor, Lauda and Foxpup and encouraging merit circles and that I am doing everything so that I can get more merit... well guess what... That account was hacked sometime in between 2014 and 2016. Suddenly switched from Chinese to Turkish. These people are so annoying and the only thing that's keeping them here on this forum is their insatiable greed.