Back when there were Fastpasses, my family used our Fastpasses for myself, my husband and DD who is disabled and uses a wheelchair.
Sometimes, we did Rider Swap and sometimes DD really wanted to ride, but chickened out at the point of boarding. The 3 of us came thru the line and watched the preshows together, then I went on while my husband and daughter walked thru the load/ride area to a waiting area just outside the ride area.
Every time we did that, when my husband went to ride, he was taken a back way to get back to the big room right before the preshow rooms. He has needed to watch the pre shows again, even though he had just watched them a few minutes before.
I‘m sure it is for safety to ensure every rider has seen the safety & boarding information