  Recently, numerous efforts have continued to push up performance boundaries
of document-level relation extraction (DocRE) and have claimed significant
progress in DocRE. In this paper, we do not aim at proposing a novel model for
DocRE. Instead, we take a closer look at the field to see if these performance
gains are actually true. By taking a comprehensive literature review and a
thorough examination of popular DocRE datasets, we find that these performance
gains are achieved upon a strong or even untenable assumption in common: all
named entities are perfectly localized, normalized, and typed in advance. Next,
we construct four types of entity mention attacks to examine the robustness of
typical DocRE models by behavioral probing. We also have a close check on model
usability in a more realistic setting. Our findings reveal that most of current
DocRE models are vulnerable to entity mention attacks and difficult to be
deployed in real-world end-user NLP applications. Our study calls more
attentions for future research to stop simplifying problem setups, and to model
DocRE in the wild rather than in an unrealistic Utopian world.
