learning manipulation

I did way "except how to open sentries", right?

I've never found a cutaway useful as a learning tool. Teaching or marketing, yes. But when learning, it's an unnecessary temptation to cheat.

Maybe a cutaway mounted in something with a locking cover, so you can't just sneak a peek, would be worth considering.

Of course it's also perfectly possible to get a lock and cut away part of the case yourself, if you've got the right tools. Whether that's worth doing depends on how much they're charging for the cutaways, how much you want one, and how much your own time is worth.

You probably did. The comment was directed to Daniel although it may well have followed a quote of your headers.