Back in the day, the sand at each local course holding a PGA event varied by grain size, consistancy and other local condtions. The touring professionals were not very happy to play out of the sand as it varied so much from week to week. The Tour then developed specifications to keep the sand somewhat consistant on a week-to week basis. The sand save percentage on Tour also increased as a result.
I say, just vary the consistancy of the sand from place to place. The bunkers would become more of a hazard again. The local population (members or daily fee guests, site dependant) would know how to play out of the bunkers as they would frequent the facility on a continual basis.