In /etc/cron.daily/tmpreaper, there are these lines:
exactly when TMPREAPER_TIME is already set.
If one does not set TMPREAPER_TIME in /etc/tmpreaper.conf,
the whole if-block is skipped, TMPREAPER_TIME is not read from
/etc/default/rcS, and is subsequently set to 7 days by the line
TMPREAPER_TIME=${TMPREAPER_TIME:-7d}
The test in question should be replaced with [ -z "$TMPREAPER_TIME" ].
Best regards,
g.