No, I'm talking only about the peak momentary coil switching current. The peak current actually going through the connection is way more than 100A (it's more like 1000A).
Reference to here:
"I just looked up the momentary amp draw of the battery contactor in a Tesla - it's between 100 and 134 amps. I believe there might be two of them, so if they both trigger at the same time, that would be a maximum of 268 amps."
12v Battery Replacement - Latest Recommendations?
From what I can find, on the continuous coil draw of the Model 3 specifically:
"Model 3 contactor 12v amperage pull measured at 8.3A continuous (without economizer)." That's 100W continuous, way more than a few watts. The instantaneous momentary peak draw is probably much higher.
Tesla Model 3 Contactors - openinverter.org wiki
Both of those loads are powered by the PCS (while HV is connected) and not the 12V battery (as others pointed out, cabin PTC heater doesn't run on 12V, but rather high voltage). They also are not on while the car is asleep, so would not contribute to drawing down the 12V battery, while instead the contactors obviously need to be run off the 12V battery when car is asleep (and HV is not connected yet).