The official answer key for a listening comprehension task marked the sentence "駅傘を忘れました" as correct. The patch community argued that "駅 で 傘を忘れました" is more natural because で marks the location of an action (forgetting), while に marks destination/existence. However, Japanese native speakers in the thread noted that both are used regionally. The final "patched answer" became:

A critical warning: Some people misuse the term "patched answers" to mean , including ones meant for classroom discussion or self-check. Sou Matome intentionally leaves some answers out to encourage you to look up words or ask a teacher.