Actually, from (Model 3) user manual:
When a child is seated in the front passenger seat (even when the child is seated in a child safety seat or booster seat), you must disable the passenger front airbag to prevent it from injuring the child if a collision occurs. Touch Controls > Safety & Security > Passenger Front Airbag, and before driving, ensure the passenger airbag status on the top of the touchscreen indicates that the airbag is off (see Passenger Front Airbag Status on page 48).
If seating a child in the front passenger seat is legally permissible in your market region, it is the driver’s responsibility to ensure that the passenger front airbag is OFF.
WARNING:If seating a child in the front passenger seat is legally permissible in your market region, never seat a child in a child safety seat or a booster seat on the front passenger seat when the airbag is active. Doing so can cause serious injury or death