Always ask in "N" means that every time you put it into "N" neutral, it will always ask if you want to go into unattended free-rolling mode.
This mode is good for automated car washes where the driver must leave the vehicle, or where the vehicle is being pulled onto a flatbed. During these special situations, you desire the vehicle to roll freely without a driver being present.
If you do not put it in this special mode and/or ignore the prompt, as soon as the driver gets out, the car will shift into "P" park automatically. This is a safety feature to prevent an Anton Yelchin type fatality (google if unaware of this young man's tragedy and how it affected all new vehicles with shift by wire).
If you are going to an automated car wash where the driver stays with the vehicle, you do not need to activate this special mode, as the car will stay in neutral as long as the driver stays in the car.