would not output citations for objects with e.g. 'edu' tag if there is no 'edu' citations for that module

[yarikoptic]

the reason is in dump that it loops through the modules after filtering by tags, so no package/module references left, thus has no chance to match (there is a filter later on) those 'edu' references. Here is a sample .duecredit.p: http://www.onerussian.com/tmp/.duecredit.p_func_cite_no_module_edu
just run

$> DUECREDIT_REPORT_TAGS=edu duecredit summary

DueCredit Report:

0 packages cited
0 modules cited
1 functions cited%      

(note seems to be lacking trailing new line)