The draw: one seed, one shuffle, one sheet
Your list is read from top to bottom, with tabs treated as separators - and commas too, when there are no line breaks at all - which is what a paste out of a spreadsheet looks like. The names are then shuffled with a seeded generator: the seed is a number, and the shuffle is arithmetic on that number rather than a reading of the clock, so the same seed always produces the same order.
The seed comes from the box on the form when you type one, and from the clock when you leave it empty. That is why the box is never silently filled in: a page that typed a number into it would erase the difference between "this is the draw I chose" and "this is the draw I got". The number the sheet actually used is printed beside it - and when keeping people apart needed more than one attempt, the number printed is the one that worked.