1. Tell Lawn Boy that Uline refused to perform warranty service

Lawn-Boy replied (yes on a Sunday!) that proof of purchase (receipt) is the
only thing necessary to obtain warranty service. So Uline's is full of
sh|t.

2. Take the mower to another authorized repair shop

That's the plan. I was hoping they could just swap me a replacement switch
but they (other place) says I need to bring it in and have them do it so
that's what we'll have to do. Not that I couldn't just use some other
suitable switch (need not be a key switch) but this is a new mower and it
should be right.