Wrong. Pick-pockets are mostly adults and there's no age or look stereotype that fits them. Growing up in the Philippines, I've seen how guys in collared shirts can easily pick your pocket while walking in busy streets of Makati.

Many of the street kids are either just playing, selling you anything and everything (water, candles, rags, etc) or begging for alms or food (usually their adults are close by).

As for safety, it's better to ride taxis at taxi stands where they give you a copy of the license plate or use a service like GrabTaxi. Take safety precautions like a Pacsafe bag and don't carry too much cash...