Yes, C&C needs to enforce zoning across the board, and quit giving variances out to developers and other connected property owners.

As far as eliminating unpermitted TVUs goes, one creative option would be to raise the TAT rate to a prohibitive level (say 100%), then allow a lower rate for those properties that have provided documentation  that they are in compliance with County zoning rules for TVU's. The lower rate would be the current TAT rate. This could be achieved by requiring an attestation or a TVU certification number at the time of tax filing. 

This would make the TVU problem a State tax problem, where fines and interest added to a 100% tax would make illegal TVUs prohibitively expensive.  These fines could fund enforcement activities.