Thieves in a crowded place

In the flea market that we go to, there was the sign about being careful with pickpockets. That may be due to the incidents that some customers have lost their purse. The market is usually a crowded place that petty thieves enjoy so much because they can operate without being noticed. But if the people will be vigilant with their wallet and purse then I guess the pickpockets will not have a heyday.

One prevention is the presence of the security guards in the area but the best is the presence of the police. For sure criminals are intimidated by the cops and even if the place is always crowded, they will avoid that. In Manila, the thieves in the markets are gone because of the presence of the cops. So maybe there should be a cop in any crowded place like the mall or the park.