First, it’ll give your eyes time to adjust to the light level outside. If it’s a day flight, you won’t emerge blinking from a darkened cabin into the sunshine, and if it’s at night you’ll see better.

Second, opening your blind helps the cabin crew to see outside. It’s not just that their eyes need to adjust: it’s that having an overall view of what’s going on outside the aircraft is very useful.

Planes are designed and tested — and crew are trained — to get everyone off in under 90 seconds if needed. During training, the crew learn to assess the safety of what’s going on outside.

They need to be able to see out — as do you. Passengers are extra eyes for the crew in case something looks amiss, so you shouldn’t ever feel silly about asking questions.

Keeping your blind open means that, in the very rare event that emergency services need to attend the aircraft, they can see inside quickly and easily.

Having more light coming into the cabin is a good idea if there’s any kind of smoke. In the event that you need to make a quick emergency exit from the plane, that makes it safer for everyone.

There are also a few extra benefits. Once it’s time for the aircraft to get ready for its next flight, having windows open means that the checks of the wings can be made more easily.

And, completely away from safety, having the blinds open makes it easier to clean the windows if necessary, whether that’s by a dedicated cleaning crew or a flight attendant with a quick wipe-down.