git fast-import not verifying commit author lines?

mtn git_export produces this output on a simple repo:

blob
mark :1
data 8
content

commit refs/heads/com.example.badexport
mark :2
author <somename> 1261454209 +0000
committer <somename> 1261454209 +0000
data 8
acommit

M 100644 :1 "afile"
progress revision 9b0e11e4d66eba8a3cf26095fb573116b886cd37 (1/1)
#############################################################

The author and committer lines are missing the names (I've filed this as a
bug with monotone).  git commit-tree refuses to to produce a commit object
like this, so it seems like git fast-import should detect and report this
instead of silently writing the invalid commit object to the repository.

--David