A319 Captain is informed by his First Officer that the inbound Captain started the APU and pointed out an APU low oil light; but made no logbook write up because they were at a non-maintenance station. The anomaly is properly entered and deferred by the departing Captain after conferring with Maintenance Control.

Narrative

After entering the cockpit the First Officer informed me the APU LOW OIL light was flashing on the ECAM page and there was an APU CLASS II MAINTAINANCE status message on the ECAM status page. The First Officer then stated that the departing Captain briefed him on the maintenance issues; turned on the APU; and showed that the APU worked fine; and did not make any write-ups because we were at a non-maintenance station and we were 'good to go.' I was shocked! I informed the First Officer this was illegal and immediately called Maintenance Control. After being just as stunned; Maintenance Control conference called an Engine Specialist and I was informed exactly of the issues and was relieved these two write-ups were separate and not related. Both maintenance issues were documented; taken care of by Maintenance Control; and we were re-released. I did not know if these two maintenance issues were interrelated and I'm stilled shocked the departing Captain failed to make these write-ups; because we were at a non-maintenance station. Is this a trend? If it is; I highly recommend Flight Safety or Standards issues a bulletin to remind all flight crew this kind of behavior is illegal; unsafe; and unacceptable.