On a cheaper version, get one from Aliexpress, only 25€/30$ http://s.aliexpress.com/3UjyInEV
Sorry, changed computer since then, I don't have it anymore :(
Since she is fine when you self-lock, just do that. But make her aware of it, and tell her the location where the keys are, and that if/whenever...
If anybody else wants it i can give a link.
locked while wife is away partying