I personally think the T&C is very reasonable ... keeping the original box, with its purpose-built protection, isn't a bad idea ... get the right "spec" in the first place shouldn't then need to open the case for additions. Get it in writing on order anyway.
Hey, if you buy two systems, and get a nice piece of glass, you could make a coffee table.
Oh it's not that I think the T&Cs (re: box) to be unreasonable, Mucks. Simply that for us, it becomes a tad impractical due to lack of space. Taffycat Hall, is a bit small, added to which, through the year, we made a couple of other purchases which also came in big boxes... lol.
As for opening the case... I wasn't thinking about additions, so much as regular cleaning. I wouldn't have thought a bit of cleaning-maintenance would be an unreasonable reason for wanting to get inside occasionally.
Now you might have something with the coffee table idea...
