In that case, I would just have a laptop in my bag just in case though it is the responsibility of the employer to ensure that interviews are accessible.

Great employers would ask you upfront -- do you require any reasonable accommodations to participate in the interview?

If you were to be surprised with an exercise, I would then immediately make a request for reasonable accommodation right then and there. Not in such a way to turn them off and for you not to get the job but in a very tactful way -- something like -- "may I have your permission to utilize my personal laptop to complete the exercise as an accommodation? I have a screen reader on my computer that would allow me to perform the exercise."

you may then go even more into it and explain how you will be able to accomplish your work by using accessible technology.

Rod,

Rod Alcidonis, Esq.