It's definitely a use case that's pretty common. I've been in post-sales/tech support most of my career but it's a similar battle. Leads to a lot of waste of technical resource time. Though I think probably being able to point as much as possible to documentation is probably where I would start.
Fair usecase. The problem with supporting sales reps is that they need answers, not pointers to documentation. That subtle difference ends up making a significant difference in product direction