I think they have to have the key already, but still 'blank' That will likely open the door but it would normally raise the alarm, that's why they start under the hood first, to disable that.

After that the procedure would be fairly easy: open the door with the still unlearned key, learn the new key ID to the ECU (takes < 1 minute) using the laptop, after that you can start the car.

One handy tip I got from the police after my own car got stolen (a VW transporter camper) was that you should mask off a chunk of the VIN so thieves can't use the VIN to order keys that will fit the car (but that still need to be programmed in the ECU in order to allow a start).