Last game i had them moved into two mercantile CS's as soon as they appeared. That action yielded +30 happiness without the need for further gifts (situational?) and allowed me to grow very fast (no need for ND thank god) and launch @ t.281 on immortal. Built police station and constabulary in Cap.
In my current game (immortal, huge map), when I was about 7 out of 12 in the tech demographic, I finally managed to beeline a tech that nobody else had -- dynamite. I was rather amazed that this new tech was stolen about five times within the next 4-5 turns.