OK, so further to my other posts about this, two things I've discovered - in the App, my old car is still registered to me, but if I try to search for parking position it gives me a message: "We cannot find your vehicle. The parking position is unavailable or the vehicle is moving." This confirm my belief that the App cannot show live tracking of the vehicle and will only update the position when it's stopped and the ignition is off.
Secondly, my profile is not yet set up on my new car as the Connect Services hasn't been set up properly by the dealer (going back in on Wednesday for a software update), but when I switch it off it currently says: "Goodbye. Got everything? Mobile phone? Everyone out the car [sic]? User profile not protected. You can protect your profile with an S-PIN in the user profile settings." That tells me that as you suspected, a thief can't just delete your profile if you protect it with a PIN. Not 100% sure what it means by "S-PIN", but might become obvious when I do get the chance to log in to the car with my MySkoda profile, which it won't let me at the moment as the eSIM isn't set up correctly.