A good remap won't cause DPF issues, it only when they produce excessive smoke you generally get issues, or doing EGR deletes without realising that the DPF requires an active EGR to regen.

The DPF itself prevents the driver knowing the car is smoking after a bad remap. Rouge Tuners best friend, as once the issues show themselves the rouge has long gone.

To measure the emissions in order to determine if the DPF is present is easy, At vosa we were using machines capable of this to test trucks for suitability for the LEZ Low Emission Zones, and they read fine particle matter,

The issue is the machines were expensive and time consuming to use as they has to be cleaned often.
The technology is there though to measure if a DPF is present from the tailpipe