It’s difficult to appear normal when you’re doing odd things. That’s why safe houses are rarely safe places. Imagine you live in an apartment building (most safe houses are actually apartments) and the people down the hall come and go at strange hours, often with their heads down. The cast of characters changes often but all of them are men. None stop to chat and none of your neighbors know them either. Every once in a while, a neighbor becomes suspicious and calls police. The only real protection you have in espionage is anonymity.