Does weekend polls favor the Democrats ?

In US, it's a common claim that weekend political phone polls skewed toward the Democrats. Here is the reasoning: on the weekend, the people who are most likely to answer their phones are older people who are more likely to be at home, so the polls may not be representative of all Americans; the poll samples could have a bias toward the older people. My dad told me this claim few time before.

However, a recent review rebuffed this common claim. For the last 3 presidential elections, among the Sunday-to-Thursday people polled in 2004, 49% supported Bush and 46% supported Kerry. Polls of the stay-at-home, Friday-to-Saturday folkls produced similar numbers - 48% and 46%.

It is reassuring that our polling methodology and standards have much more scientific merit than common claims.