I find the "maybe they didn't know" angle is fairly disingenuous, and assumes a space-faring crew wouldn't have had to go through some kind of safety training to learn about emergency procedures. Every time I go on a cruise ship I learn about the emergency tenders, how they operate, what supplies they have and features they have for being found. The idea the crew of the Nostromo wouldn't know the shuttle's capabilities feels a bit of a stretch.
If it was built for three people, there'd need to be a reason they distrusted its ability to do its job. The one the film gives is that it's not built for three -- it's built for two.
It's 100% not going to affect my enjoyment of the book or the work done on it, mind, just a fun conversation about
Quote'fixing a problem that didn't exist'.