Texting the Obvious?

I was not previously a fan of sending text messages. My old Nokia phone had predictive text, but I could never get the hang of it. As a result, I needed to perform multiple key presses, making sending even the simplest of messages a slow and painful chore. Wosog is quite a dab hand at predictive texting, as are my children. I believe my daughter's friend can even text at amazing speed using predictive text on her phone without looking at it! How the Hell does that work? Anyway, I've now got a BlackBerry Curve smartphone with a separate key for each letter, so texting is a dawdle.

I've heard of text messages being used for a few medical purposes: reminding patients about their clinic/ surgery appointments; reminding asthmatic children to monitor their peak flow measurements etc. This article on the BBC website describes a trial of the use of text messages to warn patients with seasonal affective disorder of impending overcast weather. To quote the article:

"Under the pilot project, alerts are sent to participants before gloomy days warning them to spend 20 minutes in front of their light box, and to read the accompanying advice that day.

This should help them to prepare for the dark weather and know what to expect when they draw the curtains."

Maybe I'm being stupid here, but unless these folk have very thick curtains (which would not seem a good idea in someone who craves light exposure) can't they get a pretty good idea what the light level outside is by examining the light coming through the curtains?