Hum, That was an inside joke. It got me banned from RCGroofs.
It all started when I was pushing electric flight way back in the 80's. Back then we used Sanyo NiCads (Nickel Cadmium) cells to drive our models. In the late 90's the lithium cell became available. Even at a discharge rate of 3C I thought that for most applications that we modelers would best be served by dumping our Nicads for Lithium (Lipo).
That "Friends don't let friends fly nickel" was my sigh off in the club's news letter.
Later I revised it to address the false and miss-leading advertising/marketing we saw with OS engines, in that they claimed that their ABN/ABL ringless aluminum pistons where ABC type*. When in fact they where are just second rate electroless nickel plated P&Ls.
* This was for performance and high performance 2 cycle engines.
Sorry, this has nothing to do with FrSky RX.