Just keep this in mind for future reference. In the case of this transmission, if the dealer flat refused to do a work-around on the warranty process your mom would have been up the creek because she would not have had a winnable case in court if it came down to that much pushing and shoving.
I’ve been involved in warranty repairs and claim processing both so I’m familiar with how some fudging needs to be done at times. On several occasions I’ve even been told by the Subaru district rep to “make 100% sure any questionable part is no longer questionable” and things of that nature.
Questionable computer, MAF sensor, IAC, etc? Not after the connection of my homemade wire harness between the iffy part and a 110 volt wall socket. The sound of frying bacon removes all doubt… 