Given the choice between schlepping work documents or a portable speaker system, I think most would go for the latter. It’s better use of a briefcase anyway.
It’s worth pointing out that I’m not alone in this sentiment. In fact, a small team of audiophiles in California felt so strongly about this, that they began crafting what they call BoomCases on a daily basis. Basically, BoomCases are recovered cases and boxes that are retrofitted with custom speakers, an input cable, and a long-lasting battery. Not only is it a convenient way to carry around your tunes, but it’s also great in that it recycles otherwise neglected guitar cases, Samsonites, wooden enclosures, and plastic lunchboxes of yesteryear.
Many of the BoomCases are custom orders, so there is a constant stream of unique sight/sound combinations flowing through their studio. Their stock is always different, so anytime is a good time to take a look at their website.