The industries* we are to visit, listed there on https://wiki.debconf.org/wiki/DebConf18/DayTrip/A , only accept groups, not individuals. There are many groups other than DebConf that will be vying for 8/1. I need to show them hard proof I will really use the time slots I have reserved with them. Else they will give them to other groups, and one can only join one of the other https://wiki.debconf.org/wiki/DebConf18/DayTrip s.
*The Hsinchu Science Park (HSP) is now one of the world's most significant centers for semiconductor manufacturing, industrial and computer technology development.