i heard there is a way to look for poorly insulated spots in a house with an info red detector. does anyone know what this is called?
Yes, blunt force trauma (like from a piercing gun) can shatter and damage the cartilage, but if it does, it will be there and then no later on. However, if a cartilage piercing get infected and the infection gets trapped between the layers of cartilage, the cartilage may collapse within a day or two of the infection starting. This is rare, but still a risk non-the-less.
I would say the ones that use it are few and far between - it is sticky, messy, and requires molds which either have to be bought or made - also complicated. That is not to say they don't use resin castings but I suspect they buy the castings ready molded. I would suggest a way to prove me wrong would be to Google resin casting for scale modeling and see whether you get many tutorial returns and what it says about adding stuff to the resin.