Why are the billboards covered with red cloth before the opening?

Originally it was to keep it secret, to add a sense of mystery or to attract more attention from passers-by. This is good because everyone has a psychological tendency to detect mysteries. The more you don’t know, the more you want to know. Before the store opened, the clan asked that the plaque be covered up.
The use of red cloth means hoping for a prosperous business.
Later there was talk of ribbon-cutting and unveiling.