I mentioned this re. the green non-perf. in DC in my review, too. On the other paw, as someone pointed out, I've hit this in other cars. I'm not sure if it's related to odd braking maneuvers or what, but in my other half's Nissan SUV, I've had this kind of experience and it drives me batty...keep removing/replacing seat belt, want to rip the damned thing out.
Of course with regen, it couldn't be a braking problem.... ;-) So I dunno. But it's not just one car. On the other paw, a woman from Tesla, when I mentioned it, said she'd experienced the opposite (seatbelt too loose!), so this may just be early production jitters that'll get polished as the real sales roll off the line. She was very quick to reassure me they'd iron this out, anyway. ;-)
I mentioned that in another post, so maybe it was me you saw. One of the trouble reports said the lady pulled the belt out and it got stuck for several minutes before she got it to work. I had EXACTLY the same problem a few weeks ago in the back seat of a 2011 BMW 538i. Belt got locked halfway out and I couldn't get it unstuck for several miles (about 4 or 5 minutes at a guess). Frankly, I have difficulty thinking of any car I've ever been in where there wasn't some problem with the belts getting locked or stuck or hung at some point.
Maybe the only exception I've ever seen in a car was a 1990ish Ford Tempo that I drove in college. It had powered seat belts for your chest and a manual belt for your lap which I don't ever recall hanging or having trouble with. Every other car I've ever owned, the belts get stuck occasionally. And in trying to think back on my life experiences, I think its fair to say that I have the most trouble using seat belts when I am a passenger in an unfamiliar vehicle.
It makes for a pretty straightforward hypothesis to say that when using an inherently finicky device like a seat belt you are most likely to have a problem the first time you use it. That using a particular seat belt is a learned skill. How quickly you pull it, what angle and force you use, and the timing with which you apply those forces, all matter in whether the mechanism works or not. And that literally every seat belt in every car is different, and differences are far more pronounced between (for example) the front drivers side seat belt on a BMW M3 and the right rear seat belt on a Tesla Model S. And that in the end, regardless of whether you "do it right" a seat belt is finicky because it has to be biased towards locking up to save your life in a crash, vs being easy to pull out and retract on command.
So it's simple statistics that some people taking test drives will have a problem with the belts. Thousands of people have already had reason to belt themselves in, and my guess is that in an unfamiliar car (where you haven't had an opportunity to adjust yourself to the particular belt mechanism in that car) and in an unfamiliar seating position (like a back seat) the number of failed attempts would be higher than you would see in regular use. Given the number of people who have ridden in the cars so far it should be anything but shocking that there were problems, and once one report was made a lot of people would chime in to say they also experienced problems.
None of that speaks to the quality (or lack thereof) of the belt fabric which was also reported as a problem. An issue like that is still subject to opinion, but its a much more straight forward problem. If people think the fabric looks or feels cheap that's certainly something I'd like to know (and see pictures of) until I have an opportunity to check it for myself.
P.S. - In an aside, it should be noted that every belt in every test car has been used hundreds of times in the past few weeks, which is probably equivalent to a year or three of anticipated use for front belts and a lot more than that for the rear belt mechanisms. Even folks with kids don't use rear seats as much as front seats, and children place far less of a load on a mechanism than an adult does. Hundreds of adult/buckle-ups over the course of a few weeks might not be something the engineers designed for (anyone know whether Taxi's use a heavy duty/non-stock mechanism for the rear seat belts?).
In a very related note, its very easy to forget that while the vehicles being used for test drives are just a month old, they are being intensively used in a way that is far from typical. They are already much, much more than a month old in terms of use, and certain components may be being stressed in ways not typical of normal use.
