So, here's my update after talking to some people at TAP Plastics...
The guy there says that he doesn't think that it would be possible (practical) to bond polycarbonate to the glass. His reason was that the glass and plastic have different thermal expansion coefficients. He figured that after some time either the plastic would separate from the glass or the glass would crack from the stress. So that might shoot down that thought. I'm back to looking at adding some security film.
When I first explained what I was trying to do, the woman that initially helped me said that another customer had come in and had them cut a piece of plastic in the shape of the Model 3's triangular window. It was two pieces of 1/16" sheets that were bonded together. I'm not sure why a single sheet of 1/8" wasn't used. She said that the customer had his window broken and was looking at options to make the car more secure. Given that the chrome trim and mounting pins seems to be glued onto the glass, I don't know how easy it would be to separate them and then transfer them to the plastic.
I’ve used silicone sealant for attaching plastic to glass before, the silicone has quite a bit of give in the bond.