Can't this be turned on(/off)? And are rail-guided systems different in this regard?
So I'll start from the beginning: In general, it is NOT the case that venetian blinds automatically rise. You can control the venetian blinds normally via motor, just as you are used to with roller shutters. BUT: The big disadvantage of venetian blinds is their weight, making them extremely susceptible to wind. A normal roller shutter has its own weight and is therefore far less susceptible. As already mentioned, the individual slats of the venetian blind can rattle, and even more importantly: it can happen that the slats are lifted out of their guide, get tangled, bend, etc. This can also happen with rail-guided venetian blinds; we've experienced it all. To prevent this, there are so-called sun/wind sensors. These sensors are optional, but for venetian blinds that are supposed to last a long time, they are practically mandatory. These sensors measure solar radiation, wind direction, and wind speed (so-called astro functions) and then control the venetian blinds accordingly. For this reason, manufacturers recommend placing one such sensor on each side of the house. Personally, I think that's overkill; in my opinion, one sensor at two opposite corners of the house is sufficient. One sensor at the sunrise corner and one sensor at the sunset corner, and you've got all bases covered. The control for sunlight exposure can be deactivated on the sensors, but the wind control is always active on the sensors. At least I am not aware of any major venetian blind manufacturer where it’s different. The sensors themselves are available as a wired version or also with solar power, and the control of the individual venetian blind motors then runs via radio. Why is the sensor optional but recommended: Imagine your slats are down and you go shopping, to work, or somewhere else. In your absence, the wind picks up, your slats get tangled and bent, you come home and have to replace individual slats at high cost. That’s no fun for a product that costs several hundred euros. The window installer will not cover the costs in this case because it is not under warranty. Of course, this varies from region to region. For some, the automatic wind control kicks in once a month, for others once a year.