The person I was responding to is doing her first WDW event. For people in that situation I especially encourage them to be on the first bus because they have no idea what the corral situation is like. Or, more importantly, the pre-corral situation.
But even as someone who has been doing WDW (and some DL) rundisney events since 2013, I try to be on the first few buses.
I overslept once and the panic of being on a later bus is not fun.
2014 nighttime wine and dine (the rained-the-whole-way so-called "splash and dash") as we sat in our corrals at wwos we watched a huge line of buses unable to offload passengers because of their protocol of where they could unload. I was in a later corral and we were walking to our start and those buses were still there.
Twice I have been in corrals when word went through the crowd that there were accidents on the roads. One time it stopped up a bunch of cars. Another time it stopped a bunch of buses.
Junk happens, and I'd rather be bored and cold in the corral area with thousands of brand new buddies than stuck on a bus.