This is very common at LAS on many carriers. Seems sensible in such a hot climate...

A few weeks ago I boarded a JAL 737 at a provincial Japanese airport and all the blinds were down (it was 38 outside)

No announcement was made to raise them and so we took off with many of the blinds still down...

Was that a safety violation ?

I was in the Aisle seat - and being in Japan - didn't want to cause a fuss.

It seemed a bit weird hurtling down the runway with the only outside view from the window from the row in front.

Plane landed at HND with some of the blinds still down