So I was around during this time and yes ads did play a part in this, but not like you think. The ads where how these companies planned to pay for the sat nav data (came on a DVD). They had restaurant and gas station suggestion with the same detour “feature”.

Fun part is that it fell apart quick since almost no one updated there sat nav and you can still get a 2008 acura with recommendations for places long long gone. Its also fun to see people talking about Zagat rated places on forums from the time.

https://acurazine.com/forums/4g-tl-audio-bluetooth-electronics-navigation-294/zagat-guide-questions-833757/