I guarantee you fewer than 50% of people who use a desktop computer at least once a week know how to multi-select and range-select using shift and ctrl on them,

I guarantee you fewer than 50% of people who use a desktop computer at least once a week know how to multi-select and range-select using shift and ctrl on them, though. That's why you need the text—which many will, for reasons that are actually pretty good, ignore. Or you could just use a better control.