If the thief knows nobody will pursue them, even when caught on video, then won't care if during the 15 second they are doing the smash and grab there is a car alarm in addition to the sound of the shattered glass. Look through TMC, a number of stories from the bay area, some even with videos of the thieves and police saying they are not allowed to pursue them. If the thieves are ok smashing glass in the middle of a crowded mall parking lot, they won't care about a little sound. As for the app notification, unless you are really within 15 seconds of your car, it's just telling you a little earlier that your car has been broken into because by the time you get there, the thief is gone. Heck, if you catch them in the act, that is even worse for you as you may get hurt trying to stop them - not worth it. As a side note, i live in the suburbs and there are car alarms going off a couple of times every day, nobody looks anymore. One of my neighbors daughters notoriously forgets to disarm the alarm before getting in the car, so it goes off every morning. Another teenager has their pimped car set to super sensitive, so it goes off every time the wind is >20mph and whenever a diesel delivery truck drives by. Nobody even goes to the windows when car alarms go off. I imagine in a big city, even more so.
First of all I completely agree the legislation turning car break-ins into misdemeanors is to blame here. Obviously. I also agree there exists certain nonchalance regarding car alarms going off somewhere unless it is your car (something the mobile app notification does change a bit in the equation because the owner wouild know it is their car).
That said I believe a layered defence (interior alarm, mobile notifications, locked seatbacks in hard trunks like Model 3 etc) does in fact work by making a break-in less likely and damages from a break-in less overall.
I think an interior alarm with mobile notifications will make a perp less likely to pick that car they know has the feature, will make some of those that do spend less time on the vehicle and finally make the perp less likely to target multiple such vehicles in close proximity. All of which would lessen the statistical likelihood of being a victim as well as lessening the likely damage (eg amount of stolen property).
Here’s why:
I do not think all smash and grabs take 15 seconds. This is not an epidemic of taking a handbag from the backseat which actually might happen in 15 seconds. Some of these people take their time. On TMC we have been reading about multiple cases where the perp has rummaged through bags looking for things, going through multiple layers of trunk content, entered the backseat themselves through a window, stopped their thing temporarily when they see someone coming and return to the car a bit later to continue and so forth. Incident like this may well take several minutes in fact, with only the initial noise of break-in to worry about and then silence.
The other thing is the psychology of the perp. In many of these stories we have seen the perp stop and walk away if they see someone coming in the middle of the act, only to return to the car a bit later, so there clearly is some concern of being caught. Not all of them are equally brazen. So the point is not what will others think when the alarm goes off but what will the perp think compared to a situation where the alarm does not go off?
I wager some perps will spend less time on a car with an interior alarm and thus lessen the chances of them finding something of value in there and the mobile notification allows the owner to return to the car and secure (drive it away for example) it with more haste to lessen the chance of returns, instead of the car standing there for hours perhaps with broken windows. It may be the difference of only the small window broken instead of small and large windows, it may be the difference of that laptop or camera not getting stolen. It may mean the difference of rain or further vandalism ruining the interior too.
Finally there is the psychology of what targets will a perp choose. If they knew every Tesla has an interior alarm and mobile notification like they pretty much do say in Europe would they be so keen to target Teslas with smash and grabs? The relative silence allows them to knock open multiple Teslas in the same lot without attracting much attention. Same with multiple Teslas blaring and the risk of owners running in after mobile notifications to the scene is a very different scenario.
Why not go after the other cars without interior alarms with mobile notifications...
Again my point is not that an interior alarm (with mobile notifications) will stop the epidemic. My point is it would make a difference larger than zero especially were it a standard feature in most Teslas and thus this would be known to the perps.
I find it unfortunate Tesla chose to leave out the interior alarm with mobile notifications feature in the USA when they already have implemented that for other markets as standard years ago. I do think this (cost-savings?) decision by Tesla back then adds to the number of messages on TMC about this today.