Anyone familiar with a "10 day Upset" clause? I'm alarmed.

[Brock W.]

I'm looking at a condo purchase where the legal owner is in some way incapacitated and her attorney is conducting the sale.  The asking price is under market and has the "right things wrong with it" such that if I buy it and sink 5k and a month of work I can expect to force appreciate it by about 15%.    So the numbers are tempting,  financing is in place but I am struggling with this "10 day Upset clause".  As I understand it, this clause permits the seller to accept my offer and put a 10 day block of time AFTER due diligence is completed, to potentially field other offers.  Should they get such an offer, then they can decline mine with no penalty.  Earnest money is returned but none of the due diligence (Appraisal, Inspection, Pest Inspection) expenses will be refunded.  This strikes me as arbitrary and in bad faith.  Can anyone share their experiences/insights etc?