There is no shortage of anecdotes on conference registrants, presenters, volunteers, and organizers being unable to participate due to visa issues . Further, it has often been pointed out that simply the process of applying for a visa to attend conferences can be disconcerting, logistically challenging, and dehumanizing.
Naturally, visa issues disproportionately affect members of developing nations and underrepresented communities. Visa refusals are also more common for first-time foreign travelers, which means that junior students are likely the most affected group in the population. (I wish I had more comprehensive statistics, but more on that later.)
As academics, we cannot easily make sweeping changes in international relations and policy. But perhaps there are steps that we can take in the way we organize and conduct conferences to mitigate biases against national origin and citizenship.