OK..talk about gambling. REMEMBER, now gambling is illegal in Indonesia! Dont try to come here and gambling, either in your hotel's room. I heard (when I was there), there a few groups from Msia and SPore were caught by police bcoz of this activities. When you get caught here, no matter either you are tourist or not, its difficult to deal with police. A lot of corruption, and for sure that a long process. if you 'lucky', I can visit you in prison. I meet one guy in ferry, and bring him to prison bcoz he plan to visit his brother (bcoz I have local driver to fetch me up every time I went there). So, please take this seriously ... dont think you are safe bcoz they always watching this kind of tourist.
Nowadays, Karimun Island and nearby Batam Island have increasing child prostitution and the authorities are clamping down on such activities so do be careful especially at night. Also, there are beggars and pickpockets on the streets, as well as people claiming to know you and ask you for some money.