It is something to be aware of but I think it is important to understand that these types of things happen all over the world. The Philippines can be as safe (as far as crime goes) as any other country for tourists. You just need to make sure to stay aware of your surroundings, don't make yourself a target and be careful who you surround yourself with. This goes pretty much everywhere in the world. It is sad that these things happen but poverty and poor education are everywhere and makes people desperate and causes them to do stupid sh*t.
@jimeve I thought you were already living in the Philippines.