I'm not worried at all about this because physics. If Tesla applies something that blocks 97% of UV and IR waves, then that 3% increased cabin heat from the sun is not going to make or break anything.
Let's talk about solar radiation, electromagnetic spectrum, and such:
As you can see from this energy / wavelength graph (from wikipedia). Most of the energy in sunlight is in the visible portion of the spectrum; almost none of it is in the UV portion, less than half in the IR portion (we are interested in the red curve). So even if you block ALL of the UV and IR, 50% of the energy is still going to get into the car. But what really gets the car hot, is that energy when it is absorbed, is (basically) converted to long wavelength IR, which since it is blocked by the glass, can't escape, so it builds up.
This is why most tints block visible light too. It would be interesting to know the actual tint levels Tesla intends to use, and whether they will vary that based on delivery location.
Thank you kindly.