If you win the bid you endorse them over to the trustee.  

Typically, when members have one post that is an endorsement of some company, they turn out to be a shill for that company.

-Include a check and make the cashing of the check contingent on the acceptance of the transactionSo, if he means one of those "if you endorse this check and cash it you agree to something or another" type of statements on the back of a check, they're absolutely worthless.

He cant legally cash them, but then he cant legally endorse them to the seller either...There are companies that go to auctions and bid for you. 

The endorsements can be easily faked. 

Here are the ones endorsed by our local CIREIA:http://www.ethositypropertymanagement.com/http://www.indianapolispropertymanagementinc.com/Many agents also love and recommend Dan Baldini with Polaris Management (https://polarismanage.com/)

I don’t like to endorse anybody publicly any more, I’ve learned my lesson the hard way. 

On the other hand, Travelers provides nationwide coverage, a solid financial reputation, and a broad range of options, including specialized STR endorsements.

Other policies may have an endorsement you must purchase at specific levels of coverage

Even one of the BP founders has a KW team, so you can't probably get a better endorsement than that.