The prisoners ran out of places to hide sand, and snow cover made it impractical to scatter it undetected. Under the seats in the theatre there was a large empty space but when it was built the prisoners had given their word not to misuse the materials; the parole system was regarded as inviolate. Internal "legal advice" was taken and the SBOs (Senior British Officers) decided that the completed building did not fall under the parole system. A seat in the back row was hinged and the sand dispersal problem solved.