With mod_unique_id installed there's the possibility of having a - in the forensic id, so here's a minor patch to ensure check_forensic does the right thing.
Index: support/check_forensic =================================================================== --- support/check_forensic (revision 1094142) +++ support/check_forensic (working copy) @@ -43,8 +43,8 @@ trap "rm -f -- \"$all\" \"$in\" \"$out\";" 0 1 2 3 13 15 cut -f 1 -d '|' $F > $all -grep + < $all | cut -c2- | sort > $in -grep -- - < $all | cut -c2- | sort > $out +grep ^+ < $all | cut -c2- | sort > $in +grep -- ^- < $all | cut -c2- | sort > $out # use -i instead of -I for GNU xargs join -v 1 $in $out | xargs -I xx egrep "^\\+xx" $F