There is, of course, a chance that Michael Beasley misunderstood what he saw. It's possible that a couple was driving on that road, spotted the car, and the woman got out to scope it out for whatever reason. (Thinking it belonged to a friend, fearing someone was inside who needed help, planning to break in and steal stuff, whatever). She does whatever she's going to do near the car, gets back in her own car (the red one) with her husband and they sit there while she makes a phone call to the person who she thinks the car belongs to.
I wonder if when she "locked" the car Beasley could hear it? That little honk? If he heard that, that would HAVE to either be Erin or someone who had her keys.
Anything is possible at this point. I really wish the family would comment on whether it is very likely that Erin was wearing a muted color baseball hat and a pony tail. That's so critical. But they hadn't been asked for that information, apparently, as they DID NOT know about the clue and LE is saying they didn't either. (which maybe a lie).