I, personally, feel clicker should not be used by a "beginner". To me that could be disastrous. Horses are highly intelligent fellow beings. If one is not intimately familiar with their "essence" - then using CR would be limited by the human's knowledge and the horse's nature. Otherwise, its use is limited only by the human's intelligence. Like I said earlier...I never use it under saddle, b/c I feel the instant timing of my physical "directions" w body contact would be greatly hindered. If others do use it under saddle...more power to them.
I posted the below video on a previouse thread. The 1st part was filmed unbeknowst to me by DH playing w his new phone. I normally teach my mare things that can be transfered under saddle, but I also like to just play as much as my mare does - and in the video we are just "playing", I have no "applicable use" for marching. Anyway, one poster replied "I would like to see you do that w/o clicker", I had to think about that...why would someone see it that way w a horse and not a dolphin? Or human? As it is
used w humans also, and humans also use language...and clicker is a language. So what would there be to prove for us all to stop using language?