The Safe_PWR_EN will enable to LOW (open the FET on the path) with three conditions:
1. Only Safe5V.
2. Cap_mismatch bit is asserted in RDO.
3. Voltage on VBUS mismatch sink PDO's voltage operation range. Or Current on VBUS mismatch sink PDO's current operation range.
If your design is not take care above three conditions, you can let is floating.
When you mention the current mismatch, I can set the maximum current limit via the coarse and fine resistor dividers, but if I can accept 5V as my minimum bus voltage and I connect a charger that is not capable of PD will I still get the 5V @ 500mA standard coming off a USB port or will I get a shutoff of the system where onyl 5V is available. Really what I'm asking is can I use non PD chargers with standard 5V output only as long as my VBus minimum is 5V?