>Is that typical in the industry, parts or components being glued onto an exterior surface instead of fastened?
Yes. If automotive OEMs can glue it they will.
It's just that other OEMs don't build uninterrupted 5ft light bars so glueing is a much less suitable (think about how much glue contact patch per amount of light bar there is and how little leverage it's mass has over the glue, contrast with normal light) solution for them.
Not to mention that the lightbar is directly in the airstream as you drive. It only has to start lifting a little and getting air underneath. Once that happens any glue joint is doomed.
I think if you did the glue joint perfectly then it would probably be fine, but impeccable QC is not a hallmark of Tesla.
Yes. If automotive OEMs can glue it they will.
It's just that other OEMs don't build uninterrupted 5ft light bars so glueing is a much less suitable (think about how much glue contact patch per amount of light bar there is and how little leverage it's mass has over the glue, contrast with normal light) solution for them.