You would still get a notification on the cluster saying the FOB is not detected. I'm assuming the honking is so you don't accidently leave the car running in a garage filling it up with CO2...
Mine doesn't differentiate as to the FOB being in the car or not. It has to be a lawyer decision to avoid C02 indoors or something because X number of people die that way so now we have to all have this nonstop annoyance everywhere we go. "I really love that, though" said no one, ever.
What's next? Cars only available in high visibility vest colors with reflective stripes? I'm hoping my dealer can figure out how to disable it, otherwise I'm going to unplug my horn altogether. It's so obnoxious. Everyone hates it. I've never seen a car do this before, and at most they should have installed a polite sounding 'piezo' style 'chirp' horn like other makers use for the 'alarm on/off' sound (ie BMW etc). That would have been great for the 'tire fill' honk, too. At least that can be turned off (although I like the feature, but the first time you fill a front tire you nearly go deaf.
I wonder if some kind of current resistor could limit the amount of juice for the first half second or something to turn the volume down for the first part of the horn pulse?