Not me but my aunt had them and they do change colour when cold but not drastically just shades darker (on the paler areas of course). Apparently a genetic trait, they are all born pale because of the warmth of their mothers and as soon as they are exposed to lower temps the extremities start to darken and this can affect other parts if they get cold (no idea how long before this kicks in)
Are you just curious about Siamese cats or are you interested in being adopted by one? A friend had two of them, the one thing that I know about them is that they talk non-stop. I think that they are very much lap cats.
No, wolf, I ask Alexa (the Amazon smart voice thingymejiggy) to 'tell me a fact' several times a day and this was something 'she' told me. I had never heard it before, not that I know absolutely everything but it didn't sound right to me.