If I see acoustic panels, hell, that’s another sales opportunity!
Well, considering that trying to get a room in the best acoustic shape, I would think adding panels to be something encouraged. If it adds to the sale, it seems to make sense to me, both in terms of making the sale as well as an add-on purchase.
With regards to DSP, I concur wholeheartedly. If recordings are altered and that isn't disclosed, then there is no way to know how a speaker or system actually sounds.
(Now that I think of it, just about all the dealers seem to be using music from local NAS's and whatever server they choose. It wouldn't be hard to tweak the settings to make it a bit juicier).