There are a few pages of this thread I have not read so apologies if this has already been mentioned.
The plane from which the gent was bundled off was actually operated by Republic Airlines, which I gather is reasonably similar to (say) Cobham Aviation in Australia: Republic operates some or all of United's smaller routes:
Republic Airlines is to Blame for the United Airlines Incident: Former Spirit Airlines CEO | Fox Business
Ignore the misspelling of 'boarded' in this article - it was printed as 'bordered' - but it offers an hypothesis as to how the Republic Airlines crew attempted to board late, and hence this requirement for them to travel to Louisville was not finalised before other passengers had boarded.
Simply as a guess I suspect UA may settle for $2 million to $3 million with the ejected passenger's (to use the Australian term) solicitors. USA is so litigious!