Yeah, these researchers should have included a cafe server or two in their study - the people that walk with coffee for a living, kinda makes sense.<p>Having been a cafe server for 4 years I can say from experience that you can practically run with a cup of coffee without spilling it. Several times a day I would pour a cup of coffee while I brought it to a table - often without constantly looking at it, my eyes were always scanning tables.<p>That said - if you take enough steps with a full cup of coffee it will eventually spill, that's something that us wait staff actually talked about. We rarely spilled coffee.