I can tell you that it's not uncommon for certain cultural or regional wedding traditions to involve requesting monetary contributions from guests at the door. For instance, in some cultures, it's customary to give "red envelopes" or monetary gifts to the newlyweds as a way to offer blessings and support for their future together. The practice varies widely depending on cultural norms, and it's essential to respect and understand the traditions of the specific wedding you are attending. If you ever encounter such a situation, it's best to inquire with the hosts or others familiar with the customs to know the appropriate way to participate.