@Marconius Yes! Do it! And if you're making a visual presentation there, also be sure to slip in a slide or two at random places in your deck that simply show a black screen. Then come up with some clever talk over. Act like your machine is broken, the projector is broken, the whatever reason the slide is showing nothing. Then, after pretending to struggle for five minutes with it, switch to the next slide, which will be a screen full of buttons with the actual words "unlabelled button" on them. Act all surprised that you even got the next slide to work, and then even more surprised at who ruined your slides, and how in the hell you're supposed to navigate this sea of unlabelled buttons. Then, after pretending to be frustrated at this outcome, and wasting the audiences time, switch to a new slide that says "the life of a disabled user: Accessibility barriers that cause real barriers. It might ruin your presentation reputation, by those who are too inept to get the demonstration, but there's nothing like showing a demo of the real thing in action either.