Thanks so much for the discussions and information! The defroster lines are exactly what I worry about next if go for a redo. The installer said it should not be a problem since the tint is fresh and easy to take off. This is probably true but I don't know whether I can trust what they say now. I have had my Model 3 since last December, so I know the defroster lines work well so far, after going through the many snow days in the past New England winter.
That adds another dilemma to this situation, so I can:
1. suck it up and live with the bubbles
2. suck it up and live with the bubble, but demand a refund
3. ask the installer to remove the tint and refund (risk of defroster line damaging)
4. ask the installer to remove the tint and redo a 2-piece tint (risk of defroster line damaging)
BTW, does anyone have a picture of the 2-piece tint? How visible is the line between the pieces (I guess this also depends on the skill of the installer)?
Thanks!