The Beje had become "the center of an underground ring that spread now to the farthest corners of Holland". Dozens of people came by daily with reports and appeals of those needing help, and Corrie feared that "sooner or later (someone was) going to make a mistake", and their operation would be noticed. She reflects,
"It was mealtimes especially when I worried. There were so many now for every meal that we had to set the chairs diagonally around the dining room table...the dining room was only five steps above street-level, a tall passerby could see right in the window".
Corrie was afraid that, because so many gatherered at the Beje at mealtime, their situation might look suspicious and their underground network discovered. Her fears were possibly potentially realized when one day, at the noon meal, when "seventeen of (them) were squeezed around the dining room table", one of the workers noticed that someone was looking in the curtain. Although no one had requested the service, a man was on a ladder washing the windows, and had a full view of the proceedings. To allay suspicion, the group spontaneously began to sing "Happy Birthday", to make the large gathering appear innocent. Corrie went outside to ask the man what he was doing, and he responded that he had been hired to do Kuiper's windows, which was across the street. Corrie was never sure whether the man was a spy or had simply made an honest mistake (Chapter 8).
During the war, as the Germans were taking over, everyone had to have ration cards to buy food. Each family was given just enough ration cards for their family. When the Ten Boom family began helping and hiding Jews, they had to figure out a way to get food for them. Corrie managed to arrange for a friend who worked at the Food Office to sneak 100 extra ration cards over a period of time to her so she and her family could continue hiding Jews and making sure they were fed.
She would worry about this, however, because having extra ration cards was a reason for suspicion. Having the ability to buy extra food could hint to German authorities or other anti-Semites that Corrie and her family were hiding people. This is just one of the many examples of the complex underground system that the ten Booms and others created to try and protect as many Jews as possible.