Should technicians use nitrogen to leak check refrigerators ?

Approved Leak Checking Procedures:
Whirlpool only approves the use of dye driers ( Except on 50# under counter ice makers), standard
soap bubble solution (without dye) and electronic leak detectors when searching for a refrigerant
leak. The introduction of any gas (other than refrigerant) into a system for leak checking is not
approved or recommended.