This is my thought process. I am a person of size and in a couple weeks, I will be in the FP line for FOP. I will go through with my family, after everything I've seen I'm pretty confident I will fit. But if not, I will be excited to hear my kids and husband tell me all about it. I want my skinny, string bean of a kid to be just as safe as me, so I understand there probably has to be some limit to the vehicle capacity.
I do wish parks had at the main entrance off to the side, behind a barrier of some sort, test seats for all the rides, so you could do all the testing when you get in and plan your day accordingly. Our home amusement park has this for height and even give kids colored bands so they know what rides they can or cannot go on. I understand that many people would walk right past/ignore them. But it would help with the anxiety of the test seats in front of the rides where it feels like EVERYONE is looking at you. And yes, I know most aren't even giving me a second glance.