The usual solution to self reporting systems is audits. The entire tax system works this way. It won't catch everything, but does manage to put some teeth in th

The usual solution to self reporting systems is audits. The entire tax system works this way. It won't catch everything, but does manage to put some teeth in the process and can catch systematic cheating. In this case, occasional random (and where warranted, targeted) sampling and testing by the agency would detect whether provided samples are routinely doctored.