Lots of folks would have likely stepped off willingly for a night in a hotel and/or later flight in first class and a flight voucher or cash. An alternative would be to put thier crew on another flight with another airline. This has also been done. 

I am trusting that this will be a teaching/learneing moment for the company. No doubt United will be rewriting it's customer relations manual after this unfortunate and ugly incident and hopefully be a better service provider on the back side of it. 

I have been a customer for 45 years and have traveled millions of miles with them without witnessing  such an incident.

However, as the old saying goes "It takes years to build a reputation and only seconds to ruin one"