How high does an area cap rate have to be before it's a red flag?

[Tyler L.]

A VERY GENERAL rule is that nicer neighborhoods with higher appreciation tend to have a lower cap rate while less desirable areas with low appreciation tend to have a higher cap rate. That said, when looking at the cap rates for a specific area, is there a point where you get concerned at how high it is? I've found plenty of areas where the average cap rate stands at 12-14%, but they tend to have high crime. 

Additionally, could high cap rates in dangerous areas be worth it if the strategy is buy and hold investing? With a property manager and good insurance, if the numbers work out as far as cash flow is there a situation where it should be done?