Trying to Sale a Home in the Foreclosure Redemption Period

In the past year I have had several referrals to list a home that is in foreclosure.  In MN homeowners have a 180 day redemption period in which they can attempt to sale their home.  In both cases these homeowners have had equity in these homes but had a health crisis that brought them unemployment and financial hardship.  I listed the homes at a value that the homes would sale.  I got many showings.  I also got agents who were hired to do BPO's.  Does anyone know if these agents have to disclose they are doing a BPO?  I also had on the first listing and just last week on the second listing an agent who is a known REO agent send someone to change the locks on the home.  In both cases these homes have 90-120 days left on the redemption period.  Does anyone know why these agents change the locks on homes they do not have under contract? I now can't get other agents into the home?