No, I do expect them to refuse overtime work when a company is laying off.And, you expect a/c mechanics to be any different from those folks who loudly bemoan the outsourcing of American manufacturing jobs as they stroll the aisles of Wal-Mart? Everyone is ready to feel your pain, just not do anything to alleviate it--particularly if it costs them money.
Let the company declare an emergency and force the overtime.
(BTW, I do not shop at Wal-Mart and none of my money gets spent there in my family)