It is illegal to change money on the streets. You should change money only in recognised exchange shops, banks and hotels.
The Romanian authorities treat all drug-related and sex offences very seriously. The age of consent is 18. If you are convicted, you can expect a prison sentence.
Homosexuality is no longer illegal, but attitudes are conservative and the gay community keeps a low profile.
Most airports and military bases will have signs prohibiting photography. Ask permission before photographing anything potentially sensitive (eg official buildings, police cars).