Yeah, good idea! They can re-classify OCH as a tourism / heritage spot, then promote it as one of the most eerie places in SE Asia, and tell foreigners of the horrendous things that were done there and they'll be intrigue, and then people will come.
I know in other countries like UK, they got preserve the old English castles and promote these spots as "ghost tours", and tourists can visit them with the castle's guide.
Last time TV got one show called "True or not" which shows one castle, and they tell of how one of the castle's windows occasionally got sightings of two little girls wearing old medieval clothes playing happily.
But too bad our gahmen has always been more interested in glitzy, urban, high-life, corporate type of "tourism sites", like F1, IRs etc.