Not on the list

Original non-fiction-style practice text.

The community kitchen asked visitors to suggest a dish for its anniversary meal. Tomas copied the suggestions onto a noticeboard. Beside each dish he wrote how many people had requested it. A stew received more votes than anything else, and the team began discussing how much to prepare.

Before they ordered ingredients, Noor pointed to the small pile of blank slips. The suggestion box had been placed at the end of a steep staircase. Several regular visitors had eaten downstairs throughout the voting week and had never seen it. The list recorded the choices of people who could reach the box, rather than those of everyone expected at the meal.

The kitchen repeated the request at the entrance and during table service. The stew remained popular, but two new dishes appeared among the leading suggestions. Noor did not remove the first set of votes. She added the missing responses and changed the board's heading so that it explained how the suggestions had been collected.

Explain why Noor thinks the first list does not represent all the regular visitors.