[digging]

Or, they won't say anything about it at all, because they (choose all that apply):

a) are not good communicators,

b) do not respect you,

c) are afraid to admit they don't understand (even if your doc is clearly shit),

d) do not care very much about the project.

[ChrisMarshallNY]

In my experience, it’s usually (d), even if they are on the team.