San Francisco resident Yossie (yes, the same Yossie with the world-famous handcuff collection) has a jail cell in his home, complete with an electronic time lock. The welded solid steel box will hold the keys to the cell and shackles for a predetermined amount of time, and when that time is up the hinged door to the box will be unlocked and you will be able to access the keys.
You can read and see more of this at Serious Male Bondage