I was wondering if he was using it to insulate from the probe getting conductive heat from the grate (ie using the metal poke-through clip that I, and many, use)?
The Party Q uses an alligator clip to the grate itself, calls it a thermocouple, and hints that it's increasingly accurate over a probe ... it's hints delicately as if that's somewhat unsubstantiated, or maybe anecdotal, or maybe I'm examining it too closely ...
I find the Maverick probe (in air, on clip) was reading 10-12F higher than the Party Q was figuring the grate to be, most all of the time ...
I also find my temp pen reads 5F higher than the probes (Mav and iGrill) ...
Always looking for tips and tricks and hacks ...
Cheers!