Opt In should NOT be required to enable features.
Features should not be rented, and should be delivered as purchased with the car. Shipped but disabled features that take up additional vehicle weight (relative to lacking the feature) should not be allowed. (This phrasing is precise, to allow for silicon and software enhancements which are not a material change to vehicle manufacturing / design.)
Setup processes should always empower the user. If there are multiple choices or paths a default may be indicated, but alternatives MUST NOT be in other locations, and MUST be displayed with equal prominence in a logically adjacent section of the dialog.
Example from a website: 'Paperless' should not be force enabled by default; the ability to have paper or paperless billing should be radio boxes next to each other. Additional benefits (E.G. higher account interest rates) should not be tied to either selection.