I seem to recall a time in the past when the seat belt warning alarm sounded when my passenger didn't buckle their seat belt. Recently, I noticed that was not the case. You could drive around all day with someone in the passenger seat with the belt unbuckled and not have the alarm go off. Tesla tried to repair it 3 times but then told me that the alarm only works in the driver's seat and it was never in the passenger seat. I suppose I could be misremembering something (but a Roadster-owning acquaintance thinks he remembers this as well—though, perhaps not surprisingly, his no longer works now either—so both our memories are probably shot!) In any case, I was wondering if any Roadster 2.5 or 2.5 Sport owners can confirm that there is no seat belt alarm sensor in the passenger seat. I know Tesla had a waiver to not have an advanced airbag system that sensed the weight of the passenger and adjusted the air bag deployment, but I didn't think that applied to the seat belt sensor as well—perhaps it did. Thank you!
A seat best warning would typically be triggered by a seat occupancy sensor. And seat occupancy sensors are mainly used to enable the airbag on the passenger side. I don't think Tesla implemented that technology in the Roadster.
Yeah, Roadster doesn't have passenger detection for some reason. Model S, on the other hand, starts complaining as soon as it's turned on. Even if you're in park!
Tesla asked for and received an exemption for a "smart passenger airbag" (due to low volume sales) so they didn't have to put in a seat sensor. Which was the reason they couldn't sell any Roadsters after 2012 in the US because their exemption expired.
If it helps any, your friend's wife also thinks she remembers the passenger seat belt warning, and she was pretty sure of it!
I remember someone installed a disable button for the passenger airbag with the help of Service Center. They're probably not that accommodating nowadays. Its possible they did in fact see some sort of button regarding passenger airbag.