This is a topic that has come up before (i.e. HN thread from 2011: https://news.ycombinator.com/item?id=2326790), and while GoDaddy continues to deny this practice (https://www.godaddy.com/community/Domain-Aftermarket/Is-Goda...) I tend to think that where there's smoke there's fire. Too many instances over the years to not be at least a bit suspicious.

[edit] spelling